chapter 4 the practice of science -...

42 Chapter 4

Copyright© 1999 by Tom E. Morris. http://www.planetarybiology.com

This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.

Chapter 4

The Practice of Science

4.1. Introduction

The purpose of this chapter is to introduce the basicelements of the practice of science. One of the mostimportant lessons I want you to learn from this chapteris that the scientific enterprise is very much more thanthe so-called scientific method. The scientific methodmany of you have learned is far too inflexible as acomprehensive plan for finding things out. Thescientific method probably better describes only one ofseveral kinds of experimentation. Althoughexperimentation forms a vital part of the scientificenterprise, scientists do more than run experiments.Scientists are people who engage in a variety ofactivities that support their explorations. This includescultivating interests, communicating with others,thinking about how work from other fields mightpertain to their own interests, being receptive toinstances of good fortune and being flexible enough tocharge off in new directions, policing themselves and ofcourse, performing different kinds of scientificinvestigations.

Scientific investigations generally fall into five differentcategories. They are:1) Observational/descriptive investigation

“What have we here?”2) Controlled what-if experiment

“I wonder what will happen if I push this button?”3) Explanation-seeking experiment

“What caused it to do that?”4) Modeling what-if experiment

“If I understand things correctly, I can predict howthis thing will handle under differentcircumstances.”

5) Problem-solving what-if experiment“I don’t care how you do it, just FIX IT!

Much of this chapter focuses on how each kind ofinvestigation helps in different stages of scientificexploration.

Near the end, I try to clarify the idea of what a scientifictheory is. In science, a theory organizes a collection ofrelated hypotheses in such a way that, together, theylead to larger understandings. They take otherwiseindependent ideas and build something bigger out ofthem. I also will clarify some commonmisunderstandings about the ascent of theories.Theories can be dead wrong — and still be theories.

Finally, the term, theory, can be a bit confusing since itis used in so many ways in our society. I try to clarifywhat scientists mean by the word, and how this isdifferent from its use in other settings.

4.2 Sir Francis Bacon formalized the structure of modernexperimental science

I mentioned in the previous chapter that Sir FrancisBacon established the modern scientific approach.Bacon rejected the previously held way of doing scienceand created a more productive way of doing science. Heplaced a central emphasis on the power ofexperimentation, which had not been widely usedbefore. The core of Bacon’s revolutionary method wasthat scientists should first begin with evidence and nota preconceived idea about nature. After examining theevidence, the scientist should formulate an hypothesisthat attempts to explain the evidence. This approach tonature is a logical process called induction, and itcarried the scientific revolution into the modern age.

Bacon also correctly warned scientists to beware of thepotential to introduce bias into their work. Biasreflected a scientist’s preconceived ideas about nature,and Bacon admonished them to leave bias and theiregos behind. He also encouraged a more aggressiveand intrusive study of nature. By intrusive I meanexperimental. The scientist should become moreinvolved in her inquiry. Ideas about nature shouldcome from observing nature and experimenting withnature, not from simply thinking about nature. Inshort, Bacon placed a greater emphasis on actuallyfinding out what is going on than on the egos of thescientist. He replaced the ideas of scientists based onauthority with ideas based upon observational andexperimental data — a major turning point inhumanity’s exploration of the Universe.

Before Bacon’s method in the early 1600s, it wascommonplace for scientists to first adopt an assumedtruth and then deduce the consequences of that truth.They held preconceived notions about nature, either inspite of or in the clear absence of evidence. Here is anexample of a scientist who did not study Bacon. In1800, Franz Joseph Gall introduced the science ofPhrenology in which the areas of human brain function

Author’s note (March 6, 2009): This DRAFT document was originally prepared in 1998 and has not been fullyupdated or finalized. It is presented here in rough draft form. Despite its unpolished condition, some might find itscontents useful.

The Practice of Science 43Copyright© 1999 by Tom E. Morris. http://www.planetarybiology.com

This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.were characterizedbased on the shape ofbumps on the skull(fig. 4.1). Gall, aphysician, argued thatby studying thebumps on your headit would be possible todetermine your mentalcapacity. He and hiscolleague, JohannesSpurzheim developedelaborate maps of thehead that showedlocalized areas ofbrain function. Andfrom what? They hadno evidence to supportsuch claims, just the

initial belief that they were right. Today, phrenology istotally discredited as modern science has demonstratedthat a person’s brain operates quite independently ofhead bumps — which should come as a relief to thoseof you with bumpless heads. Why is it appealing forpeople to adopt a preconceived idea then promote it asthe truth?

Although Bacon’s new methodology has resulted in anexplosion of scientific discovery, the idea of thescientific method continues to be misrepresented.Bacon formalized an approach to science, not a recipe.

4.3 The so-called “scientific method” gives an incompletepicture of the larger scope of scientific endeavors

Bacon’s extensive inspiration has been incorrectlyreduced by textbook authors to a ritual of procedurescalled the “scientific method” (Panel 4.1). The “scientificmethod”, as it is typically described, presents a narrowview of the whole scientific enterprise. At best itdescribes only one of several types of experimentalscience, but neglects other realms of modern scientificactivity. In

short, the so-called “scientific method” really doesn’treflect the larger practice of modern science. Bacon’sidea is more than a ritual of procedures. It is a highlyversatile and logical strategy for finding things out.

Therefore, the notion of the scientific method is really afalacy. The practice of modern science involves avariety of activities, and it is not restricted to justperforming experiments. If the pursuit of scientificunderstanding were confined to following only the rigidstructure of the “scientific method”, hardly anythingwould get done. Science is much more fluid andadaptable than the “scientific method” indicates. True,there are important times when experimentalinvestigators do follow such steps. But a scientist ismore than a “cook”. Discovery involves more thanfollowing a “cookbook” ritual of steps. The scientificprocess is not so mechanical and inflexible as the“scientific method” would have you believe. Instead, thescientific process is a very creative enterprise in whichevery available creative resource of the scientist isaccessed. For example, the following are briefdescriptions of activities that support the total scientificenterprise.

4.3.1 Scientists are curious about how natureworks

The most important force that drives science is ascientist’s individual curiosity about nature. This couldbe cancer research, climate, or the mysteries ofbusiness cycles and even car repair. Without acuriosity, who cares?

4.3.2 Scientists stay current with the latest newsin their field

Scientists seek out the latest news in their area ofinterest. They read articles, and talk to other scientistswho share similar interests. They think about newideas in relation to their particular field of interest.

4.3.3 Scientists sometimes benefit from advancesin other fields

The scientist also is open to findings in other fields.They consider if there are opportunities to integrateadvances in other fields into their field. For example,the science of the climate draws on information fromthe fields of biology, geology, physics, mathematics andmore.

4.3.4 Some scientists integrate work done byothers and see larger understandings

Integration (organizing pieces of knowledge and tryingto see larger explanations) of the existing body ofinformation is one important activity scientists do.Often there are many ways to interpret new informationgathered in scientific investigations. Not all scientistsare involved in acquiring raw information. Somescientists are better at experimentation. Somescientists are better at seeing the “big picture”, in

Figure 4.1. The discreditiedscience of phrenology used bumpson the skull to diagnose mentalcapacity.

Panel 4.1. "Scientific Method"

The so-called "scientif ic method" usuallyincludes the following series of steps:1) Observations2) Formulation of an hypothesis to

explain observations3) Performance of experiments to test

hypothesis4) Assessment of experimental results

in terms of hypothesis5) Repeating steps 2, 3, and 4 if

necessary

44 Chapter 4


This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.which case they may spend much of their timedeveloping new and larger insights based upon thework of other scientists. For example, the discovery ofthe shape of DNA was made by two scientists (Watsonand Crick) who performed almost no actualexperimental work of their own. Instead, they carefullyevaluated the work of others and saw what no one elsesaw.

4.3.5 Scientists sometimes benefit fromserendipity (good luck) — and go with it

Occasionally, a scientist will stumble upon a new andunintended circumstance that takes the scientist in anentirely new direction of research. This is calledserendipity and is a natural part of exploration.Scientists are not required to “stay on target” when newand more inviting targets present themselves duringthe course of their work.

For example, in 1922, Scottish bacteriologist,Alexander Flemingdiscovered theantibiotic, penicillin,quite by accident.While preparing tothrow away somebacteria he had grownin a dish (fig. 4.2), henoted that in one dishthere was an area inwhich no bacteria hadgrown. Uponinvestigation, Flemingdiscovered thepenicillin fungus hadaccidentallycontaminated the dishand was killing thebacteria. In anotherexample, an improperlyassembled

experimental device led to the somewhat “premature”invention of the telephone by Alexander Graham Bell in1875. Scientists are open to good luck.

4.3.6 Scientists compete for grant money

It takes money, lots of money to keep scientificinvestigations going. For instance, the NationalInstitute’s of Health AIDS research budget for 1996was $1.4 billion (Wadman 1996a)The Institute’s totalbudget for 1997 was set at $12.7 billion (Wadman1996b). Scientists compete with each other for a limitedpool of grant money. In the United States, grant moneyis available from such organizations as the NationalScience Foundation, American Cancer Society, and theNational Institutes of Health. But that money is nottheirs for the asking.

Each scientist must submit a grant proposal to thefunding institution in which they explain how themoney will be used. As part of the qualifying criteria,scientists must show that they are productive users ofgrant money. They typically demonstrate this ahead oftime by publishing papers on their previous projects.The accumulation of published papers then is used tobolster requests for grant money. There is tremendouspressure to keep the money flowing. A universityexpects its professors to acquire great sums of grantmoney, a portion of which is skimmed into theuniversity’s account. Grant money productivity is oneof the central criteria used when evaluating youngprofessors for tenure. So, young new assistantprofessors struggle fiercely in their first few years onthe job, trying to be productive members of thescientific community.

4.3.7 Scientists police themselves

Not all science is good science. So, the scientificcommunity has several ways of policing its own. Pleasesee panel 4.2 for some interesting ways science dealswith issues of scientific integrity. The usual processinvolves screening papers that scientists submit toscientific journals. According to this process,publishers refuse to publish work that isn’t up tomodern scientific standards. But some scientistscircumvent this process, sometimes with tragic or justplain peculiar consequences. The case of cold fusion isone example (panel 4.2). Another example involves afrustrated physicist. In an impetuous declaration ofindependence, physicist, Stefan Marinov avoided thepeer review process by simply taking out an ad in ascientific journal (panel 4.2). The scientific communityendeavors to guard against plagiarism and fakery.Panel 4.2 describes two cases of alleged plagiarism andfakery. And finally, the Piltdown Man hoax lasted for 40years before finally being discovered by persistentinvestigators (panel 4.2).

These methods demonstrate the various ways scientistshave in discovering and preventing the distribution ofbad science. Science is a self-correcting enterprise.Although a small number of scientists occasionallymaneuver around the normal publication screeningprocess, most build their reputations by strictlyadhering to it. Still, sometimes good and honest sciencefinds it hard to reach the community, despite the bestintentions of the scientists themselves. This isespecially true when corporate profits are involved.

4.3.8 Corporations sometimes act to suppressscientific findings

Wealthy corporations sometimes block the scientificpublication of work they pay for. In 1996, BootsCompany successfully convinced biomedical scientist,Betty Dong, not to publish her scientific findings ondrug research (Wadman 1996c). Dong had been paidby Boots Co. to compare rival products to Boots Co.’s

Figure 4.2. A drawing of aswabbed petri dish.Microbiologists grow bacteriaand fungi on a nutrient mediumin this kind of dish. After severaldays, large colonies are visible.



own and highly profitable Synthroid, a thyroidmedication. However, Dong’s research revealed thatinstead of being inferior, rival products might beequivalent to Synthroid. Fearful of huge commerciallosses, Boots Co. attorneys pressured Dong not topublish her findings, citing her contract with Boots Co.Faced with an expensive lawsuit, Dong capitulated.

No cases have received such wide attention as those ofrebel tobacco scientists. In 1994, the US SurgeonGeneral estimated that tobacco-related illnesses killabout 434,000 Americans each year (Raloff 1994). USFood and Drug Commissioner, David Kessler reportedin 1994 that he had reason to suspect that tobaccocompanies were fortifying cigarettes with nicotine in ascheme to keep their customers hooked. He noticedthat over a ten-year period from 1982 to 1992, tarlevels in cigarettes remained constant, yet nicotinelevels steadily increased. The situation began to boilover in 1993 when one of the tobacco industry’s topscientists alleged that his company lied about scientificfindings about the risks of disease and addiction fromsmoking. Jeffrey Wigand was vice president forresearch and development for Brown & WilliamsonTobacco Corp. from 1989 to 1993. Wigand was fired byBrown & Williamson and now is being sued by hisformer employer for fraud and breach of contract.Ordinarily a single person would be no match for theenormously wealthy and powerful tobacco companies,and would be forced to retract all allegations. But, thetelevision program, “60 minutes” has agreed to pay

Wigand’s legal fees in exchange for appearing on theprogram. According to Wigand’s attorney, Wigand” haspaid a terrible price” (Levin 1996) for blowing thewhistle on the tobacco industry.

4.3.9 Scientists sometimes can be brutallycompetitive

Leading biomedical scientist, Tsunao Saitoh, was shotto death near his front door in San Diego, California onMay 7, 1996 (Dalton 1996). He was 47. Saitoh’s 13-year-old daughter also was killed. A 24-year-oldkickboxer, Paul B. Cain, was charged with the crime.Some researchers have not ruled out the possibilitythat Saitoh was killed at the behest of rival scientists ina race for a revolutionary cure for Alzheimer’s disease.

Although relationships amongst scientists normally arepolite and civil, they can occasionally turn violentlysour. For example, a few years ago one San Diego areascientist tried to poison a rival because of differencesconcerning a research project. In another case, awoman was found strangled near San Francisco,California after she testified in a court case concerningpatent rights. This case led some to speculate that herdeath may have been linked to the patent case. SomeSan Diego research institutions have the reputation forintense competition. This has resulted in stolenlaboratory notebooks, and scientists afraid tocommunicate their findings at scientific conferences forfear of losing competitive and commercial advantage.

Certainly, violence of this nature is extremely rare, butit can happen when deeply involved in finding a thingout — especially if there is the potential for commercialgain.

4.3.10 To sum up, science is a very humanenterprise

I want to dispel the notion that you have to be somekind of ‘nerd’ to practice science. Science isn’t a bunchof ‘eggheads’ standing around in white lab coats, andpocket-protectors pontificating and staring throughmicroscopes. Instead, science is a lively and dynamichuman enterprise populated with normal people whojust happen to be especially curious about how thingswork. There can be moments of high drama as rivalresearchers engage in tug-of-wars both in the literatureand in person. There are episodes of comedy asresearchers unwittingly do foolish things — just likeany other line of work. But most of all, there is the thrill

46 Chapter 4



Scientif ic journals filter out bad scientificwork

Scientists usually share their discoveriesby publishing reports of their work.There are many scientif ic journals(scientif ic magazines) available forscientists. The most prestigious journalsuse a system in which referees revieweach submitted paper before it ispublished. The referees are fellowscientists considered experts in theirf ields. Mostly what referees do is theyscreen each paper for its adherence toscientif ic technique. If the paper makesunsupported claims or has sloppyexperimental procedures, the refereesrecommend that the paper not bepublished.

Press conferences by-pass normalscreening procedures

Occasionally, scientists become impatientwith the publishing ritual, either becauseit is too slow or because they can’t gettheir papers past the referees. The coldfusion f iasco is a good example in whicha pair of scientists by-passed the journalreview process by announcing theirf indings at a press conference — withunfortunate consequences. In 1989,Chemists Stanley Pons and MartinFleischmann announced that they haddiscovered a way to generate energyfrom fusion nuclear reactions at roomtemperature (and not at the thousandsof degrees that the physics of fusionotherwise dictates). They called it “coldfusion”. If true, this would haverevolutionized our thinking about nuclearphysics and chemistry. It was anexhilarating notion that not only wouldhave meant a vir tually unlimited supply ofenergy but also billions of dollars inpatent profits. The lure to understandcold fusion was irresistible to manyphysicists who flocked to this mostpromising f ield. Initial attempts byphysicists to replicate the experimentproduced conf irmation at f irst. But af ter

Panel 4.2 How the scientific community deals with issues of scientific integrity

more than a year of study by scientists itwas f inally shown that cold fusion couldnot be adequately demonstrated. Thebubble on cold fusion had burst.

In an effort to salvage what was left oftheir damaged reputations, Fleischmann,Pons and two Italian physicists (EmilioDel Giudice and Guiliano Preparata)sued for $6.3 million an Italian authorwho wrote disparagingly about coldfusion. An Italian court heard the caseand sided with the author (Abbott 1996).In an emotionally charged letter to theBritish journal, Nature, after the ruling,the two Italian physicists referred to thecritical scientif ic community as beingreminiscent of 1930s Germany, populatedwith too many ‘ayatollahs’ (Del Guidiceand Preparata 1996). Sticking to theaccepted channels of peer review mighthave prevented all of this unpleasantness.

Rarely, frustrated scientists by-passpublication referees and pay toadvertise their f indings

More about detours around the journalknothole. If you can’t get past thereferees, why not take out an ad? Ithappens only once-in-a-while. In onecase, physicist, Stefan Marinov, apparentlywas so frustrated with disagreeablereferees that he published his scientif icf indings in the form of a two-page paidadvertisement (Marinov 1996). Marinov’ssometimes incoherent rant againstestablished physicists may not haveadvanced his scientif ic standing. Why is itallowed? The highly prestigious journal,Nature, justif ied this form of permissivepublishing on the grounds that it issomewhat “whimsical”.

Plagiarism and fakery sometimeshappens, although it is not tolerated

Sometimes scientists accuse others ofstealing or faking their work. Forinstance, in March 1996, a Brazilian courtordered Carlos Augusta Pereira to pay a$50,000 f ine to Yeda Lopes Nogueira for

plagiarizing Nogueira’s work. Since 1982,Nogueira had spoken at conferences ofcertain unique effects of the rabies virus.But despite her lengthy involvement inthis area, she had failed to publish herwork in a scientif ic journal. Seizing on thisopportunity, Pereira later duplicatedNogueira’s work and published hisf indings as his own, without citingNogueira. Nogueira and the Braziliancourts held that such an actionconstitutes theft of intellectual property.

In a stormy case in the United States,cellular biologist, Thereza Imanashi-Kariwas accused of faking her experimentalf indings on gene expression in mice. Thecharge was leveled in 1986 by MargotO’Toole who was working as a researchscientist in Imanashi-Kari’s laboratory atthe Massachusetts institute of Technology(MIT). Imanashi-Kari was found guilty ofmisconduct and fraud by the NationalInstitutes of Health in 1994. But sheappealed the ruling. In 1996, Imanashi-Kariwas cleared of wrongdoing by the USDepartment of Health and HumanServices (Steele 1996). The latest rulingoverrides the earlier judgment of fraud.In defense of Imanashi-Kari, similardecisions had been previously reached inher favor by investigative bodies at MIT,Tuf ts University and the US Attorney’sOff ice of Maryland (Editorial 1996).Because of indications of a hasty f irstruling, the question is should Imanashi-Kari ever have been charged in the f irstplace? Still, this example demonstratesthat allegations of fakery are treated veryseriously by the scientif ic community.

The Piltdown hoax was a long-livedpractical joke

Probably the greatest hoax ever to bevisited on science was the case of thePiltdown Man (Feder 1990). In the year1908, an amateur scientist by the name ofCharles Dawson discovered a remarkablehuman skull in southern England. Severalyears later, Dawson found a piece of alower jaw at the same site. What



of the hunt and the adrenaline rush that comes withdiscovery. For if the practice of science is anintellectual and emotional struggle, it is the discovery ofnew things that keeps us going.

4.4 Scientists perform five basic kinds of investigations

The above sections indicate that the scientific pursuit ofunderstanding is more than the methodical making ofobservations and performing experiments. But,investigations remain at the heart of scientific learning.Aristotle and Hippocrates of ancient Greece firstestablished the pattern of methodical observation.About 1600 years later, Sir Francis Bacon proposed aformalized method of experimentation. Today, scientistsperform five basic kinds of investigations. They are:1) Observational/descriptive investigation

"What have we here?”2) Controlled what-if experiment

“I wonder what will happen if I push thisbutton?”

3) Explanation-seeking experiment“What caused it to do that?”

4) Modeling what-if experiment“If I understand things correctly, I can predict howthis thing will handle under differentcircumstances.”

5) Problem-solving what-if experiment“I don’t care how you do it, just FIX IT!

The point is that scientific endeavors are not confinedto the classical mode of operations defined above as the“scientific method”. Scientists are explorers and theresimply are many different ways to go exploring. It justdepends on what your goal is.

4.5 Each kind of scientific investigation is useful indifferent stages of exploration

Imagine that you have just stumbled upon some kindof odd-looking object while hiking in the desert. It is asbig as a house. It is shiny and sleek. It looks like anairplane of some kind, but what is it? I will give you a

astonished anthropologists (scientistswho study human evolution) was thatthe jaw appeared ape-like and the skullappeared to be that of a modern human.Scientists of the time accepted the f indswithout much reservation, partly becauseit confirmed their preconceived notionsabout the evolutionary development ofhumans. According to the belief at thetime, the human brain f irst evolved to itslarge form, then the rest of the body(including the jaw) later evolved into themodern form. But the Piltdowndiscovery was a sham. Someone haddeliberately planted the bones. In 1953,Kenneth Oakley of the British NationalMuseum determined that the jaw wasnot ancient and not human. It was clearlythat of a modern orangutan, a large apefrom the Asian island of Borneo. Forforty years, science had been victim of an

ingenious practical joke. Scientistsstill are not sure who did it, butcontinue to wonder about it. BrianGardiner, professor ofpaleontology at King’s College,London, announced to theLinnean Society on May 24,1996 that he has a prime suspect(Gee 1996). Construction workersfound a box of bones and otherincriminating materials under the roofof London’s Natural History Museumin the mid 1970s. The box was markedwith the initials of Martin A. C. Hinton, acurator at the museum at the time of thefraud. Despite powerful evidence of thiskind, other scientists continue to considera list of other potential suspects (Hall1996). We may never know for sure whothe hoaxers were or why they did it.

48 Chapter 4


This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.hint. It is a spacecraft. This discovery has aroused yourcuriosity, and you have decided to investigate. As wewill see, your investigation will start out very simply,then progress to more sophisticated stages. This oftenis how science works.

4.6 “What have we here?” Observation/descriptiveinvestigations cast the scientist as a somewhat passivespectator

The first step in your encounter with this spacecraft isto check it out. At this stage of your investigation, youknow almost nothing about it. So, you first begin bywalking around it at a safe distance making carefulobservations. A scientist would be making sketchesand jotting down notes of her observations. Once youhave seen all that you can from a distance, you decideto move in for a closer look. You observe a fine texturein the spacecraft’s skin — something you couldn’t see

before. You feel itsjagged surface, stillwarm. You smell achemical odor andfollow your nose to apurple fluid leakingout of the craft.There is strangelettering next towhat looks like a bigorange button.There is nothing elsethat you think isworth looking at.

You have just completed a survey of the spacecraft.This is a type of observation/descriptive investigation,probably the most basic scientific investigation. This iswhere the scientist is simply surveying, hoping to seenew things. Aristotle was a prime example of such anexplorer. Observation/description investigations castthe scientist in a somewhat passive role. He is busytrying to observe and describe all the manycomponents that make up a system.

For example, field botany often is purely descriptive. Abotanist sets out to collect and describe all the differentkinds of plants on a mountain. Here is anotherexample. A boat load of oceanographers criss-crossedthe world’s oceans collecting data on ocean depth andwater chemistry. Based upon the information theycollected, these explorers were able to create a detailedmap of the ocean floor. Cataloging information in thisway is essential in clearing the path for science’s otherpowerful tools —experimental investigations.

Experiments are different from observation/descriptiveinvestigations. They do more than simply observe anddescribe. They interrogate the system by eitherintroducing changes or by making carefully controlledobservations. The goal of experimentation is to probebelow the observable surface and reveal what makesthings tick.

Experimental investigations are by far the most efficientways of finding things out. Basically, they formalize theprocess of trial-and-error — a process strangelyunacceptable to ancient philosophers but so natural tochildren in the time of Empedocles of ancient Greece.Experimentation builds on the notion of trial-and-errorand make it more efficient. The use of experimentsrepresents a major advance in human scientifictechnique. Below, I discuss the different kinds ofexperiments.

4.7 “I wonder what will happen if I push this button.”Controlled what-if experiments increase theopportunity for observation but seek neitherexplanations nor predictions

Having thoroughly exploredthe spacecraft exterior, yourcuriosity remainsunquenched. Just in caseyou have missed somethingimportant, you make onemore pass around the craft.You are satisfied that thereis nothing important left tolearn by simply surveyingthe craft’s exterior. You areready to move to the nextlevel. It is time to intrude.

At this point, you begin towonder what might happenif you push the big orange

button on the side of the ship. Since you know nothingabout how the craft works, you have no way ofpredicting what will happen when you push the button.Nonetheless, you believe that if you push the button,the craft might respond, and if you observe carefully,you might learn something interesting. So, you do it,and a door opens. You have just completed a controlledwhat-if experiment.

Controlled what-if experiments are different fromobservation/descriptive investigations because theyrepresent an intrusion into the studied system. Thescientist introduces some kind of change, then sitsback to see what happens. Hopefully, theconsequences of his intrusion will yield some newopportunities to make interesting observations —observations that were not possible while performingthe passive, observation/descriptive investigation. In


This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.your case, you intruded by pushing the orange button.The consequence of that intrusion was that the dooropened on the spacecraft, presenting you with anabundance of new observational opportunities.

Controlled what-if experiments can be played out in allareas of our lives not just in the accepted fields ofscience. When cooks “experiment” with a splash of thisand a pinch of that, they are hoping for an unusualnew taste. Artists of all kinds are constantly trying newtechniques or variations to create newness in theirwork. Musicians come up with new rifs by trying new

rhythms and chord combinations. Controlled what-ifexperiments are an important part of examining the fullrange of possibilities of a system. See Panel 4.3 formore examples of controlled what-if experiments.

If scientists are lucky, their controlled what-ifexperiments will result in new and interestingobservations. Given enough time with your spacecraft,you may achieve a full working knowledge of how tooperate the craft. But you may not know the theorybehind it. You may not be able to explain how itspropulsion systems work, or its navigation. In order tofind explanations, a different kind of experiment mustbe done.

I wonder how the Chernobyl nuclearpower plant will react at low powerwith nearly all the control rods removed

At about 4:00 in the morning of April1986, the operators of the Chernobylnuclear power plant were testing theoperational limits of the reactor. Theywanted to see how the reactor wouldreact at low power output and whilemost of the control rods were removed.They were carefully performing acontrolled what-if experiment.Unfortunately, what they learned wasthat under these conditions, the reactorwould explode.

I wonder how plants will deal withincreases in atmospheric carbon dioxide

climatologists are interested in howincreases in atmospheric carbon dioxidemight be counteracted by plants.Remember that plants remove carbondioxide from the atmosphere duringphotosynthesis. A what-if scenario wouldask, “How do plants react to increases inatmospheric carbon dioxide?” In thiscase, there is no background of observedphenomena, and until there is, nohypotheses can be formulated. In orderto generate observations, a what-ifscenario is developed. This scenariowould place different plants in controlledatmospheres with differentconcentrations of carbon dioxide. If thereare no observable dif ferences betweenplants in dif ferent atmospheres, newwhat-if scenarios might be designed. If

plants in one kind of atmosphere growtaller than others, then hypotheses canbe generated as to why — because nowthere are interesting observations thatbeg for an explanation.

I wonder how acid rain will affect corngrowth

Acid rain has damaged lakes and forestsin Europe and in the northeastern partof the United States. Agriculturalbiologists worry that acid rain also couldhurt crops like corn. In order to see ifthere is reason to worry, a controlledwhat-if experiment is set up. Corn plantsare irrigated with acidic water andcompared to corn irrigated with normalwater.

I wonder what might happen if you goout on a blind date?

Your best friend arranges a date withyou and a new girl in school whom is atotal stranger to you. This is called ablind date. Your alternative is to stay athome and watch television. That soundsboring so, you carry out a controlledwhat-if experiment with a scientif ic spirit,not seeking explanations or formulatingpredictions — just looking for interestingobservations. You can see how blindwhat-if experiments can signif icantlyincrease your chances for gatheringinteresting experiences.

I wonder if I will like the music on thisnew CD

Here is another example most of us canrelate to. You walk into a music storeand see a CD by a group you are totallyunfamiliar with. You’ve never heard ofthem. You’ve never seen them. So, youdecide to listen to the CD at the store.You have just conducted a controlledwhat-if experiment.

I wonder if this mud contains anymicroorganisms with medicalapplications

A worker at a Swiss pharmaceuticalcompany routinely collects mud fromaround the countryside. Back in the lab,she grows the dif ferent molds thathappened to be in the mud. One-by-oneshe grows each kind of mold in the samedish different kinds of bacteria. Thepurpose of this controlled what-ifexperiment is to see if any of her moldsinf luence how bacteria grow. Since shehasn’t studied these molds before, shehas no basis for making any kind ofprediction. Also, since she has noexperience with their effect on bacteria,there is no phenomenon for which toseek an explanation. However, hercontrolled what-if experiments willsignif icantly increase her chances ofdiscovering something interesting.

Panel 4.3 Examples of Controlled what-if experiments

50 Chapter 4


This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.4.8 “What causes it to do that?” Explanation-seeking

experimentation is a hypothetico-deductive process

In order to explain what causes thisinteresting spacecraft to behave theway it does, you have to becomemore sophisticated in yourexperimental approach. Right now,you are at “technician” level. Youknow what buttons to push andlevers to pull. But you do notunderstand the basis for theoperation of the ship. You cannotexplain it.

Explanation-seekingexperimentation is the kind ofexperimental work you normally

would associate with “the scientific method”. This flavorof experiment seeks explanations to account forinteresting things the scientist has observed. It is ahypothetico-deductive process. The term “hypothetico-deductive” refers to the use of hypotheses (possibleexplanations) in order to deduce an explanation.Simply stated, deduction is a logical process in thatattempts to reach an understanding by using reason.Explanation-seeking experiments are composed of thefollowing main components:1) Observation of an unexplained phenomenon2) Formulation of a causal question3) Development of multiple hypotheses4) Preparation of predictions with which to evaluate

hypotheses in light of experimental results5) performance of experiments or other controlled

observations6) Assessment of results by comparing them to

predictions7) Making a final determination of the one most likely

hypothesis, or rejecting all hypotheses

4.8.1 Observations of unexplained phenomenaget the scientist thinking

Not all unexplained phenomena are appealing toscientists. They choose only the most interestingmysteries. Here is an example for you. You havebecome proficient at flying the strange spacecraft. Youhave observed that you can fly to Mars and backduring your lunch hour. No doubt about it, this is afast ship. It is amazingly fast. This unexplainedphenomenon definitely has your attention. So youbegin to think about it.

4.8.2 Causal questions address the nature ofyour interest in the observation

Having noted the super speed of the spacecraft, youcould do a couple of things. One thing you could do issimply be very passive about it and accept things, justfly it without a worry. This would not be a scientificapproach. Or you could begin to ask all kinds of

questions, like, “How fast am I going? What will happenif I break down in space and miss my final exam? Whydoesn’t this thing have a CD player?” All importantquestions of course, but they don’t address the cause ofyour interesting observation. Instead you becomeengaged in a process which seeks an explanation aboutthe craft’s speed. You do this by asking the simplequestion, “What causes the spacecraft to go so fast?”This is an example of a causal question in which youseek to understand what caused the phenomenon youobserved. For the purpose of this example, answeringthis question becomes the central purpose of yoursoon-to-follow scientific efforts.

4.8.3 Causal questions may have many possibleanswers — many possible hypotheses

The purpose of determining the cause of thespacecraft’s speed is simply that you want tounderstand it. As we will see later, this knowledge canhave important benefits. Now, this spacecraft is acomplex thing. But you already have studied thespacecraft (by performing numerous descriptiveobservations and controlled what-if experiments) andhave a pretty good idea about the location of differentsystems and how to operate them. The act of studyingthe available information and formulating possibleexplanations is a creative logical process calledabduction. Based upon the your previous work, you

Science attempts to describe itsobservations of nature by using thesimplest possible explanations. Thisvaluable principle is an extension of thephilosophy of William Ockham whoseLaw of Parsimony (also known asOckham’s Razor) argued that anexplanation of an unknown phenomenonshould f irst be attempted in terms ofwhat is already known. In other words,the simplest possible explanation.Confusion about UFOs, ESP, fortune-telling and all other pseudosciences canbe avoided if people considered thesimplest explanations f irst. That is, it ismore likely that enterprising humans areinvolved than unexplainable, magical, orsupernatural forces.

Panel 4.5 The explanation withthe fewest assumptions is probably thebest



Hypotheses must pass an important test:falsif iability. In order for an hypothesis tobe considered legitimate, there must besome accepted condition under which itcan be shown to be false. If no suchconditions can be imagined, thehypothesis is not legitimate and cannotbe considered by science.

For example, I can hypothesize thatfairies cast a spell on my car and made itstop. But this is an illegitimate hypothesis,not because it is probably false, butbecause there are no conditions underwhich I can show that it is false. If I f irmlybelieve that fairies disabled my car, underwhat conditions will I be willing to setaside this idea? No scientist on Earthcould ever convince me that fairies do

not exist. Why? Because science cannotprove a negative. There is no scientif icway to prove that supernatural forces donot exist. But there are simplerexplanations (see panel 4.5). Therefore,blaming fairies on my car’s troubles is nota legitimate hypothesis, since there areno conditions under which I will accept itto be false.

To follow-up on this item, two additionalpoints. First, just because science cannotprove that certain things do not exist, itdoes not logically prove that they doexist. It just means that such issues areunavailable for science to consider.Conspiracy theories are good examples.For decades, people have "known" of a

"conspiracy" by the oil companies andauto manufacturers to buy up newtechnology that would otherwise allowcars to get 100 miles to the gallon.Investigations into this conspiracy haveturned up no evidence -- which, in theminds of the believers, is furtherevidence of the conspiracy. The point isthat if there are no conditions underwhich people a willing to set aside theirconspiracy idea, then science cannot helpthem.

Finally, just because an hypothesis islegitimate, that does not make it correct.It just means that science can test thehypothesis. Once a scientist assembles acollection of legitimate hypotheses, shetests them to f ind out which is the bestone.

Panel 4.4 Hypotheses must be falsifiable in order to be legitimate

Imagine the following situation. Yourteacher gives you a sealed bag of m&mscandies.Next, he asks you to formulatean hypothesis regarding the proportionof different colored candies inside yourbag of m&ms.

What is wrong with this picture?1. An hypothesis is an attempt to explain some

observed phenomenon. But it requiresinformation that suggests somethinginteresting and unusual. So, sitting therestaring at a sealed bag of m&ms, what couldyou possibly be trying to explain? At thispoint you have made no interestingobservations. If an hypothesis isn’t possible,is he really asking for a prediction?

2. In science, predictions are used to assessthe accuracy of hypotheses and theories. Ifour predictions about a system constantlycome true, then we understand that systempretty well. Without the solid ability topredict accurately, life would be verydifferent for all of us. For example, a center-fielder on a professional baseball teamintuitively understands very well the theoryof gravity and the laws of momentum. Heachieves this understanding not by takingphysics classes but through years ofexperience catching high fly balls. The pointis, in order to make a legitimate scientificprediction, you must have a reasonablefoundation of experience upon which tobase your prediction. A prediction made withlittle or no experiential base has little valueand is nothing more than a blind guess.

Panel 4.6 Hypothesis vs. guess

3. What this teacher is really asking you to do(but doesn’t know it) is to guess on theproportions of different colored candiesinside the bag of m&ms. Guessing is an actof contemplating without the benefit ofexperience or practice. In terms of scientificunderstanding, guessing (or speculation)can spark creative thinking (this is good) butit is not part of the rational scientificprocess.

4. In short, this exercise is very misleading inthat it attempts to portray blind guessing asequivalent to the hypothetico-deductivereasoning process that makes explanation-seeking experimentation such a powerfulscientific tool for finding things out.

52 Chapter 4


This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.have learned that there are several possibleexplanations for the craft’s propulsion. Each possibleexplanation is called an hypothesis. Scientists exploringnature develop multiple hypotheses when they try tofigure things out. Once you have formulated manyhypotheses, you need to determine which ones arefalse, and which one (or ones) is (are) the best. Butbefore you proceed with your experiment, you need todevelop some predictions upon which to judge yourhypotheses. See Panels 4.4, 4.5 and 4.6 for moredetails about hypotheses.

4.8.4 Predictions and experiments are used toevaluate hypotheses.

During the experimental phase of your investigation,each hypothesis should have a predictable result.Therefore, the next step is to formulate a predictedoutcome for each hypothesis — in the context of aplanned experiment. Each hypothesis is tested one-at-a-time by experimentation. The results of each round ofexperimentation are compared to the predictions madefor each hypothesis. When the results ofexperimentation don’t match the prediction, then youreject the hypothesis.

4.8.5 “If... and... then... and/but... therefore”statements organize the logic ofexperimental investigations

Hypotheses, experiments and predictions are logicallytied together using “if... and... then... and/but...therefore” reasoning. For example, let’s organizetwo hypotheses as follows:

Hypothesis No. 1: If the spacecraft goes so fastbecause it is powered by anti-gravity engines,

Experiment: and after running out of fuel, Iput in more anti-gravity fuel

Prediction: then the spacecraft will flyagain.

Result: and after doing this, I observedthat the craft flew once again

(but after doing this, I observedthat the ship could not moveagain.)

Conclusion: therefore, if my results matchmy prediction, my hypothesisis supported. If my results donot match my prediction, myhypothesis is not supported.

Hypothesis No. 2: If the spacecraft is powered bynuclear engines,

Experiment: and after running out of fuel, Iput in more nuclear fuel

Prediction: then the spacecraft will flyagain.

Result: and after doing this, I observedthat the craft flew once again

(but after doing this, I observedthat the ship could not moveagain.)

Conclusion: therefore, if my results matchmy prediction, my hypothesisis supported. If my results donot match my prediction, myhypothesis is not supported.

4.8.6 Explanation-seeking experiments test onefactor at a time

I hope you noticed in the above examples I did not testboth hypotheses simultaneously. Why not? Let’s say Itest two hypotheses at the same time. For example,when the spacecraft runs out of fuel, imagine that I putin both anti-gravity fuel and nuclear fuel and the shipmoves again. No doubt about it, my problem would besolved, but what have I learned? What caused it tomove? Anti-gravity engines or nuclear engines?

4.9 “If I understand things correctly, I can make reliablepredictions” Modeling what-if experiments useunderstandings to arrive at reliable predictions

Modeling what-if experiments take the understandingsgathered from explanation-seeking experiments anddevelop a theoretical model of the whole system. Thepoint of developing models is to be able to make reliablepredictions. We can use the model to make predictionsabout how a system will respond to different andunusual kinds of conditions. Modeling is very usefulwhen it is very expensive or risky to perform a full-sizeexperiment.

Unlike explanation-seeking experiments, modelersdevelop no hypotheses. Models do not try to findexplanations outright. However, they may point tointeresting phenomena not anticipated by scientists. Inwhich case, the results of simulations may lead to new

rounds ofexplanation-seekingexperiments.

For example,engineers willsimulate thestresses that a largedam mightencounter duringheavy floods. Theyevaluate differentdesigns and identifyweak spots. Theymodify the design


This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.accordingly and model it again. They repeat thisprocess until they have a satisfying design. Then whenthey actually build the dam, they have much greaterconfidence in it. Without some kind of modeling aheadof time, it would be too expensive, risky and time-consuming to build full-scale trial dams.

Sometimes models are used to simulate phenomenathat take many years to run their course. For instance,scientists who study the global climate (climatologists)develop models that can predict how the global climatewill respond to human pollution. Since global climateundergoes very slow change, climatologists use modelsto make speedy predictions. That way if the predictionsare really bad, we can start doing things now to preventthem from coming true.

Let’s get back to your spacecraft. You have performedmany explanation-seeking experiments and knowpretty well how and why the ship handles the way itdoes. It is very impressive. It is so impressive that youhave it in your head that you can fly through a starwith it. This is too risky to try in real life, so you decideto develop a model in order to safely simulate it.

You base your model on understandings you achievedby performing numerous explanation-seekingexperiments. Developing a model tests whether youreally understand how things work. Simulation modelswould not be possible without strict adherence toscientific principles. The benefit of modeling what-ifexperiments is that our knowledge can advance faster,with less expense and less risk to lives.

Finally, simulation models have no desired outcome,which sets this kind of experiment apart from problem-solving what-if experiments.

4.10 “I don’t care how you do it, just fix it!” Problem-solvingwhat-if experiments often test more than one variableat a time

Problem-solving what-if experimenters try to reach aspecific desired outcome as quickly and efficiently aspossible. The goal of problem-solving is to solve aproblem, regardless of the cause.

Let’s imagine you have mechanical trouble with thespacecraft. Confronted with a problem like this, youprobably are going to be operating not in explanation-seeking mode but in problem-solving mode. There is a

subtle difference.When your shipstarts to runroughly, it could bebecause of lots ofminor things. So,you take yourspacecraft in for atune-up. Tune-upsare perfect examples

of problem-solving activities in which it is more efficientto install multiple solutions simultaneously. Tune-upsreplace several pieces of equipment including sparkplugs, plug wires, points, condensers, fuel filters. Thenyour spacecraft’s timing and fuel systems are adjusted.Would it be cheaper for the garage to test eachcomponent one-at-a-time and see if your spacecraftruns better after they try out each one? When you getyour ship back after a tune-up, it runs great. Why?Was it the new spark plugs? Was it the new fuel filter?You will never be able to know. But who cares? Yourgoal was to have a well-running spacecraft. The tune-up helped you achieve that goal. It helped you solveyour problem.

This is just an example of how the process of problem-solving often can be achieved more efficiently byperforming multiple experiments at the same time. Youcan see that problem-solving uses some elements ofexplanation-seeking experimentation, but its goal is notto understand. Its goal is to solve problems, howeverthat is most efficiently achieved. Explanation-seekingexperiments and problem-solving what-if experimentsoften are practiced differently. When your goal is tounderstand, then use explanation-seekingexperiments.

Panel 4.7 shows how the different kinds of scientificinvestigations can be applied to seven differentsituations. See fig. 4.3 to see how these types ofinvestigations are organized.

Figure 4.3. Scientific investigation flow diagram

Explanation-SeekingExperiment

Observation / descriptiveInvestigation

Modeling What-IfExperiment

Problem-SolvingWhat-If Experiment

Controlled What-If Experiment

START

54 Chapter 4



Syste

m yo

u are

study

ing

Inve

stig

ation

Obse

rvati

on / d

escr

iptive

inves

tigati

onCo

ntro

lled

what-

if exp

erime

ntEx

plana

tion-

seek

ing ex

perim

ent

Mode

ling w

hat-i

f exp

erim

ent

Prob

lem-so

lving

wha

t-if e

xper

imen

tsti

mulat

ingco

mmen

tW

hat h

ave w

e her

e?I w

onde

r wha

t will

happ

en if

I pus

h this

butto

n.W

hat c

ause

s the

craft

to fly

so fa

st?Ca

n this

craft

fly sa

fely t

hrou

gh a

star?

The s

pace

craft s

talls

in tra

ffic. I

don’t

care

how

you d

o it, j

ust fi

x it!

Unus

ual s

pace

craft

Actio

nYo

u ske

tch an

d des

cribe

the s

pace

craft.

Push

the b

utton

and w

atch w

hat

happ

ens.

You t

est m

ultipl

e hyp

othes

es in

cludin

gthe

poss

ibility

of je

t pro

pulsi

on, r

ocke

tpr

opuls

ion, a

nti-g

ravit

y driv

e, an

ti-matt

erdr

ive an

d imp

roba

bility

drive

.

Base

d on w

hat y

ou ha

ve le

arne

d abo

utthi

s cra

ft, yo

u dev

elop a

comp

uter m

odel

that s

imula

tes its

char

acter

istics

. This

ismu

ch sa

fer th

an ac

tually

tryin

g to f

lythr

ough

a sta

r.

Base

d upo

n you

r und

ersta

nding

of th

ewo

rking

s of th

e spa

cecra

ft, the

prob

lemco

uld be

caus

ed by

thre

e diffe

rent

failed

comp

onen

ts. S

o, in

an ef

fort to

save

time,

you r

eplac

e all t

hree

.Re

sult

You s

ee m

any i

ntere

sting

thing

sinc

luding

a big

oran

ge bu

tton.

The d

oor o

pens

. You

do si

milar

expe

rimen

ts on

the l

ever

s and

butto

nsins

ide th

e cra

ft, an

d lea

rn to

fly it.

You

beco

me m

ore c

uriou

s abo

ut it.

Your

tests

rule

out a

ll pro

pulsi

onsy

stems

exce

pt im

prob

abilit

y driv

e. Fo

rno

w, th

is is

the be

st ex

plana

tion.

Your

simu

lation

mod

el pr

edict

s the

craft

will i

nstan

tly fr

y and

will

be cr

ushe

d flat

ifyo

u atte

mpt to

fly it

throu

gh a

star.

Good

thing

you d

idn’t t

ry it.

Prob

lem fix

ed. W

hy? W

ho ca

res?

Well

,yo

u migh

t whe

n you

see t

he bi

ll.

stimu

lating

comm

ent

Wha

t hav

e we h

ere?

I won

der w

hat w

ill ha

ppen

if we

oper

atethe

reac

tor at

low

powe

r and

with

few

contr

ol ro

ds.

Wha

t cau

sed t

he re

actor

to ex

plode

?W

ill the

same

type

of ex

perim

ent c

ause

an ex

plosio

n in a

simi

lar re

actor

?Th

e rea

ctor’s

powe

r outp

ut is

less t

han

norm

al. I d

on’t c

are h

ow yo

u do i

t, jus

tfix

it!

Cher

noby

l nuc

lear

powe

r plan

t

Actio

nYo

u ske

tch an

d des

cribe

the r

eacto

r.Op

erate

the r

eacto

r this

way

and s

eewh

at ha

ppen

s.On

a sim

ilar r

eacto

r, yo

u do m

uch s

afer

tests

to ex

amine

mult

iple h

ypoth

eses

includ

ing re

actor

stab

ility,

coola

nt los

s,an

d nuc

lear r

eacti

ons.

Base

d upo

n wha

t you

have

lear

ned

abou

t the r

eacto

r, yo

u dev

elop a

comp

uter m

odel

that s

imula

tes its

char

acter

istics

. This

is m

uch s

afer t

han

doing

risky

expe

rimen

ts.

Base

d upo

n you

r und

ersta

nding

of th

ewo

rking

s of th

e rea

ctor,

the pr

oblem

could

be ca

used

by th

ree d

iffere

nt fai

ledco

mpon

ents.

So,

in an

effor

t to sa

vetim

e, yo

u rep

lace a

ll thr

ee.

Resu

ltYo

u bec

ome c

uriou

s abo

ut the

reac

torco

ntrols

.Th

e rea

ctor e

xplod

es an

d kills

you.

Othe

rs be

come

curio

us ab

out w

hy th

isha

ppen

ed.

Your

tests

rule

out c

oolan

t loss

and

nucle

ar re

actio

ns. F

or no

w, re

actor

stabil

ity is

the b

est e

xplan

ation

.

Your

simu

lation

mod

el pr

edict

s tha

t an

explo

sion w

ill oc

cur u

nder

simi

larcir

cums

tance

s.

Prob

lem fix

ed. N

ow, c

arefu

lly m

onito

rthe

perfo

rman

ce of

the r

eplac

edco

mpon

ents

to pr

even

t futur

e pro

blems

.

stimu

lating

comm

ent

Wha

t hav

e we h

ere?

I won

der h

ow pl

ants

will r

eact

to hig

her

conc

entra

tions

of C

O 2.

Wha

t cau

ses p

lants

to giv

e off l

ess

water

vapo

r whe

n CO 2

is hi

gher

?Ho

w mi

ght a

decre

ase i

n wate

r vap

orre

lease

affec

t the f

ores

t?Fu

ture i

ncre

ases

in at

mosp

heric

CO 2

could

caus

e majo

r clim

ate pr

oblem

s. I

don’t

care

how

you d

o it, j

ust p

reve

nt it!

Plan

ts an

d inc

reas

edatm

osph

eric

CO2

Actio

nYo

u note

that

plants

take

in C

O 2 an

dgiv

e off w

ater v

apor

. You

also

note

that

atmos

pher

ic CO

2 is in

the r

ise.

Subje

ct so

me pl

ants

to hig

her C

O 2, a

ndoth

ers t

o nor

mal a

ir and

see w

hat

happ

ens.

You t

est m

ultipl

e hyp

othes

es in

cludin

g,da

mage

to ro

ots, s

uppr

essio

n of

resp

iratio

n, an

d clos

ure o

f leaf

pore

s.

Base

d upo

n wha

t you

have

lear

ned,

you

deve

lop a

simple

mod

el tha

t sim

ulates

the fo

rest.

This

allow

s you

to pr

edict

what

migh

t hap

pen i

n the

futur

e as C

O 2lev

els co

ntinu

e to r

ise.

Not s

o fas

t! This

prob

lem ca

nnot

beea

sily s

olved

beca

use i

t invo

lves

comp

lex pu

blic p

olicy

decis

ions.

The

meas

ures

for r

educ

ing C

O 2 ou

tput a

reex

pens

ive an

d may

hurt

the ec

onom

y.Tr

y to f

ind th

e che

apes

t, eas

iest

solut

ions f

irst a

nd se

e if th

ey he

lp.Re

sult

You b

ecom

e cur

ious a

bout

there

lation

ship

betw

een i

ncre

ases

in C

O 2an

d plan

ts

The m

ore C

O 2, th

e les

s wate

r vap

or is

relea

sed.

You a

re cu

rious

why

.Yo

ur te

sts ru

le ou

t roo

t dam

age a

ndre

spira

tion s

uppr

essio

n. Fo

r now

, the

best

expla

natio

n is l

eaf p

ore c

losur

e.

Your

mod

el pr

edict

s tha

t the f

ores

t will

be dr

ier an

d will

rece

ive le

ss ra

infall

beca

use o

f less

evap

orati

on fr

om tr

ees.

Monit

or ef

forts

to re

duce

CO 2

emiss

ions.

If the

re is

no im

prov

emen

t, con

sider

more

aggr

essiv

e mea

sure

s.



Syste

m yo

u are

study

ing

Inve

stig

ation

Obse

rvati

on / d

escr

iptive

inves

tigati

onCo

ntro

lled

what-

if exp

erime

ntEx

plana

tion-

seek

ing ex

perim

ent

Mode

ling w

hat-i

f exp

erim

ent

Prob

lem-so

lving

wha

t-if e

xper

imen

tsti

mulat

ingco

mmen

tW

hat h

ave w

e her

e?I w

onde

r how

corn

plan

ts wi

ll rea

ct to

acid

rain?

Wha

t cau

ses c

orn p

lants

to gr

ow sl

ower

when

subje

cted t

o acid

rain?

How

migh

t incre

ases

in ac

id ra

in aff

ect

corn

prod

uctio

n in t

he U

S?Fu

ture i

ncre

ases

in ac

id ra

in co

uldca

use m

ajor lo

sses

in fa

rm pr

oduc

tion.

Ido

n’t ca

re ho

w yo

u do i

t, jus

t pre

vent

it.

Corn

and a

cid ra

in

Actio

nYo

u note

that

acid

rain

has b

een o

n the

rise.

You o

bser

ved t

hat it

has d

amag

edlak

es an

d for

ests

Subje

ct so

me co

rn pl

ants

to ac

id ra

inan

d othe

rs to

norm

al ra

in an

d see

wha

tha

ppen

s.

You t

est m

ultipl

e hyp

othes

es in

cludin

gda

mage

to le

aves

, dam

age t

o roo

ts,lea

ching

of ce

ll con

tents.

Base

d upo

n wha

t you

have

lear

ned,

you

deve

lop a

comp

uter m

odel

that p

redic

tsthe

effec

t of a

cid ra

in on

corn

. This

allow

s you

to pr

edict

wha

t migh

t hap

pen

in the

futur

e as a

cid ra

in co

ntinu

es to

incre

ase.

Not s

o fas

t aga

in! T

his pr

oblem

cann

otbe

easil

y solv

ed be

caus

e it in

volve

sco

mplex

publi

c poli

cy de

cision

s. Th

eme

asur

es fo

r red

ucing

acid

rain

are

expe

nsive

and m

ay hu

rt the

econ

omy.

Try t

o find

the c

heap

est, e

asies

tso

lution

s firs

t and

see i

f they

help.

Resu

ltYo

u bec

ome c

uriou

s abo

ut the

effec

ts of

acid

rain

on cr

ops.

The m

ore a

cidic

the ra

in, th

e slow

erco

rn pl

ants

grow

. You

are c

uriou

s why

.Yo

u find

evide

nce t

o sup

port

all of

your

hypo

these

s.Yo

ur m

odel

pred

icts t

hat c

orn p

rodu

ction

will d

rop a

s acid

rain

incre

ases

.Mo

nitor

effor

ts to

redu

ce ac

id ra

in. If

there

is no

impr

ovem

ent, c

onsid

er m

ore

aggr

essiv

e mea

sure

s.

stimu

lating

comm

ent

Wha

t hav

e we h

ere?

I won

der w

hat w

ould

happ

en if

I wen

t out

on a

blind

date.

Wha

t cau

sed y

our b

lind d

ate to

like y

ou?

You l

earn

ed no

thing

that

would

help

you

mode

l you

r exp

erien

ce. L

ove i

s blin

d.Yo

ur lo

ver le

ft you

. I do

n’t ca

re ho

w yo

udo

it jus

t fix i

t!

Blind

date

Actio

nYo

u are

offer

ed an

oppo

rtunit

y to g

o out

on a

blind

date.

Go ou

t on t

he da

te an

d see

wha

tha

ppen

s.Yo

u tes

t mult

iple h

ypoth

eses

by as

king

your

blind

date

why t

hey l

ike yo

u. Is

itbe

caus

e of y

our lo

oks,

the w

ay yo

udr

ess,

your

perso

nality

, you

r bod

y?

Good

luck

!

Resu

ltYo

u bec

ome c

uriou

s abo

ut ho

w the

blind

date

migh

t go.

Your

blind

date

tells

you t

hat th

ey re

ally

like y

ou. Y

ou ar

e cur

ious w

hy.

Your

blind

date

isn’t s

ure,

they j

ust li

keyo

u. Sc

ience

is no

help.

stimu

lating

comm

ent

Wha

t hav

e we h

ere?

I won

der if

I will

like t

his m

usic.

Wha

t cau

sed y

ou to

like t

his m

usic

somu

ch?

Wha

t wou

ld be

the c

hanc

es of

comm

ercia

l suc

cess

for a

band

that

avoid

s the

se m

usica

l pitfa

lls?

We w

ere o

nce a

very

popu

lar ba

nd. N

owthe

publi

c ign

ores

us. I

don’t

care

how

you d

o it, j

ust fi

x it!

Music

CD

Actio

nYo

u obs

erve

a CD

by a

grou

p you

have

neve

r hea

rd of

.Lis

ten to

the C

D an

d see

if yo

u like

it.Yo

u per

form

a sur

vey w

ith 10

0 of y

our

friend

s in w

hich y

ou co

mpar

e this

mus

icto

music

you a

ll hate

. You

test

multip

lehy

pothe

ses i

nclud

ing be

at, ki

nds o

fins

trume

nts, ly

rics,

music

iansh

ip, ho

oks

and s

inging

style

s.

Base

d upo

n wha

t you

have

lear

ned,

you

deve

lop a

mode

l that

pred

icts t

he m

arke

tac

cepta

nce o

f diffe

rent

band

s.

The m

odel

that c

atapu

lted y

ou to

succ

ess i

s out

of da

te. B

etter

do a

new

study

and d

evelo

p an u

pdate

d mod

el.An

d do s

ometh

ing ab

out th

at ha

ir!

Resu

ltYo

u bec

ome c

uriou

s abo

ut it.

It sou

nds l

ike a

mix b

etwee

n Hoo

tie an

dthe

Blow

fish a

nd Le

d Zep

pelin

. You

love

it and

you w

onde

r why

.

You d

iscov

er yo

u and

your

100 f

riend

sdo

n’t lik

e mus

ic wi

th a w

impy

beat,

bras

s ins

trume

nts, tr

ite ly

rics,

nomu

sical

hook

, and

polis

hed s

inging

.

Your

mod

el he

lps m

any n

ew ba

nds

modif

y the

ir styl

es to

bette

r sati

sfy th

emu

sical

tastes

of yo

ung m

usic-

buye

rs.

Your

new

mode

l pre

dicts

that y

our

band

’s tim

e has

come

and g

one,

and

there

is no

futur

e for

you.

Las V

egas

,he

re I c

ome!

stimu

lating

comm

ent

Wha

t hav

e we h

ere?

I won

der if

ther

e are

any m

edica

llyint

eres

ting m

icroo

rgan

isms i

n this

mud

.W

hat c

ause

d the

bacte

ria to

die?

You h

ave l

earn

ed no

thing

from

whic

h to

deve

lop a

mode

l. Mor

e mud

, plea

se.

Mud

Actio

nYo

u obs

erve

some

mud

pudd

les in

afor

est y

ou ha

ve ne

ver b

een t

o.Co

llect

the m

ud, g

row

its or

ganis

msun

der v

aryin

g con

dition

s and

see w

hat

happ

ens.

You t

est m

ultipl

e hyp

othes

es in

cludin

gba

d gro

wing

med

ium in

the d

ish,

conta

mina

tion,

activ

ity of

the f

ungu

s, yo

ufor

got to

put in

the b

acter

ia.Re

sult

You b

ecom

e cur

ious a

bout

the ki

nds o

fmi

croor

ganis

ms in

the m

ud.

Bacte

ria th

at ca

use b

ody o

dor d

on’t

grow

in th

e sam

e dish

as a

new

fungu

sfro

m the

mud

. You

begin

to w

onde

r why

.

You r

ule ou

t all h

ypoth

eses

exce

pt on

e.Yo

u mus

t hav

e for

gotte

n to p

lace t

heba

cteria

in th

e orig

inal d

ish.

Pane

l 4.7.

Diff

eren

t sta

ges o

f scie

ntifi

c exp

lorat

ion.

56 Chapter 4


This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.4.11 “Theory” means to see

The word, “theory” comes from the Latin word theoria,and from the Greek word theoros, which roughly means“seeing”. The English expression, “I see”, is a goodapproximation of what a theory is all about — itrepresents a vision, a seeing.

Scientific theories represent the pinnacle of scientificpursuit. A theory is an explanation that organizesrelated hypotheses into a larger, unified whole. Theypresent the “big picture” view of the world. Scientifictheories connect diverse hypotheses into a centraltheme so we can better understand all of them.Theories pull ideas together and give them meaning. Atheory is the construct of insightful scientists who seethe greater possibilities of seemingly unrelated ideas.The construction of a theory is much like assembling ajigsaw puzzle. For example, hypotheses are to a theoryas puzzle pieces are to a puzzle. Scientists use theconnectedness of hypotheses to assemble them into acomprehensible web of ideas. But some theories aremore correct than others.

4.12 Theories can be incorrect — and still be theories

Many of us have learned that theories are the naturaloutcome of a long-standing hypothesis that has notbeen proven false. This is a wrong definition of atheory. Longevity or correctness are not involved in theestablishment of scientific theories. Here are someexamples of theories that are clearly wrong, but whichare still theories. The Flat Earth theory holds that theEarth is flat, not spherical. Although this theory wasproven wrong by Eratosthenes of the AlexandrianLibrary about 2300 years ago, it’s still a theory. Here isanother one. In the year 1809, French naturalist, JeanBaptiste Lamarck proposed a theory of evolution(Lamarckism) such that acquired traits could betransferred to offspring. If this theory is correct, andyou workout with weights and become muscular, yournew kids should be born muscular. Modern geneticshas demonstrated how wrong Lamarckism is, yet it isstill a theory. The value of theories is that they provideopportunities for scientists to think in new ways. Andthis is good, even though many theories are wrong.

Although wrong theories are still theories, sciencecannot build on wrong theories. It builds on correcttheories. Some theories are shown time and time againto be correct. Such theories are called “embedded”theories.

4.13 Modern biology is supported by several embeddedtheories

Embedded theories have survived repeated tests, arewidely accepted, and are thought unlikely to beoverturned. All of the work of modern biology restsupon the foundations of several powerful, embeddedtheories. For example, the cell theory evolved as anatural outcome of observations made by themicroscope invented by Anton van Leeuwenhoek ofHolland in the mid 1600s, and the discovery of cells byRobert Hooke, a contemporary of Leeuwenhouk’s.Johan Gregor Mendel, a modest Austrian monk,developed a theory of inheritance in 1865. Mendel’srevolutionary ideas about how traits are passed on tofollowing generations formed the basis for moderngenetics. In the 1850’s, British naturalists CharlesDarwin and Alfred Wallace independently developedtheories to explain the evolution of life on Earth.Darwin is generally credited for preparing the mostcomprehensive theory, known as the Theory ofEvolution by Natural Selection. Darwin’s theoryprovides a unifying theme for most of biology. In 1953,U. S. genetic researcher, James Watson and Englishgeneticist, Francis Crick working together presented avision of the structure of chromosomes that was to leadto powerful new insights in genetics. Their theory ofDNA structure and duplication now helps explain cellstructure and function, Mendelian genetics, evolutionby natural selection, inherited diseases and muchmore.

4.14 The term, “theory”, is used in different ways in oursociety

The word, “theory”, is used in ways that have differentmeanings in our society. You have read above howscientists develop “scientific theories”. But these arequite different from “casual theories” we develop in oureveryday lives. For example, your favorite police dramausually features a detective saying, “I’ve got a theoryabout this murder”. Or your friend may have a “theory”on how to get better grades. In these two cases, theterm, “theory”, has been substituted for the term,“hypothesis”. I hypothesize that “theory” is used inplace of “hypothesis” because it has fewer syllables andis much easier to pronounce. The language of the landhas come to accept this substitution, but you shouldknow the difference between a scientific theory and acasual theory (an hypothesis by another name).


This DRAFT document is an excerpt from Principles of Planetary Biology, by Tom E. Morris.4.15 References

Wadman, Meredith (1996a). Panel calls for overhaul ofAIDS research. Nature 380: 190.

Wadman, Meredith (1996b). NIH bucks political trendto win increased funds from Congress. Nature 381:633.

Abbott, Allison (1996). Scientists lose cold fusion libelcase, Nature, 380: 369.

Del Giudice, Emilio, and Preparata, Guiliano (1996).Jury still out on cold fusion?, correspondence. Nature,381: 729.

Marinov, Stefan (1996). Paid advertisement entitled,Marinov: annus horribilis. Nature, 380: .

Steele, Fintan (1996). Clearing of researcher in‘Baltimore Affair’ boosts demand for reforms. Nature,381: 719.

Editorial (1996). A judgment fit for prime time, Nature,381: 717.

Feder, Kenneth L. (1990). Frauds, Myths, andMysteries: Science and Pseudoscience in Archaeology.Mayfield Publishing Company, Mountain View, CA, 40-56.

Gee, Henry (1996). Box of bones ‘clinches’ identity ofthe Piltdown paleontology hoaxer. Nature, 381: 261.

Hall, E. T. (1996). Riddle of the tenth man,correspondence, Nature, 381: 728.

Wadman, Meredith (1996c). Drug company‘suppressed’ publication of research. Nature 381: 4.

Raloff, Janet (1994). The great nicotine debate: arecigarette recipes ‘cooked’ to keep smokers hooked?,Science News 145: .

Levin, Myron (1996). Tobacco case Marked by sets ofsound bites. Los Angeles Times, 16 July, p. D2.

Dalton, Rex (1996). Death of molecular biologist stunsSan Diego science, Nature 381: 178.

chapter 4 the practice of science -...

Documents