BiologicalAnthropology

the nature of science

Some Terms used in Science

• Hypothesis: a statement that potentially explains specific phenomena – must be falsifiable

• Data: evidence that helps answer questions and problems

• Empirical: referring to data obtained through observations and/or experimentation

• Theory: a set of hypotheses – explanatory principles – that have not (yet) been falsified

Science is …

a process that develops provisional truths

That is, “truths” that may one day be replaced by better “truths”

Science is not…

a process that develops absolute truths

That is, TRUTHS that may not be questioned and can never be corrected or improved upon

Two Assumptions of Science

1) You explain natural phenomena only by referring to other natural phenomena

Methodological materialism

2) If two models both explain the data, use the simplest (unless you have a reason not to)

OCCAM’S RAZOR

(which is NOT the same as Philosophical Materialism)

Science can be understood as

a process of “modeling” reality

reality

A Theory Emerges

the first model

does not explain some aspects of its

focus

predictsoutcomes that will not occur

x + 1 = y

Science Advances

a second, “better” model

unexplained phenomena

predicted, but not “real”

x2 + 2z = 0

Comprehension Increases

another, even “better” model

predicted,but not“real”

unexplainedphenomena

Science as the Quest for

ever “better” models

Is there

a “perfect” model?

explainsall phenomena

that do exist

predictsnothing

that doesnot exist

Not yet…

Science as arevolutionary process

“normal” science

anomalies

scientific “revolution”

The Copernican Revolution

the shift from a geocentric

(“earth-centered”)

to

a heliocentric(“sun-centered”)

model of the solar system

Geocentric Worldview

• Earth was immobile

• All celestial objects revolve around the earth•Sun•Moon•(fixed) stars•Planets, comets, etc.

• Aristotelian physics divided the heavenly region from the earthly region(= perfection vs. corruption)

Science takes place in a Social Context• Geocentrism was central to early Christianity

• Universe created for humans• Humans are the reason for creation

• Challenging the geocentric view was heresy

• Heresy was a very serious offense

The Retrograde Mystery

Two Different Explanations

The Geocentric ViewThe Heliocentric

View

Different celestial objects move in very different ways

The Earth moves in the same way as other celestial objects

Nicholas Copernicus

• 1473-1543

• Physician, lawyer, church administrator

• De Revolutionibus Orbium Coelestium (“On the Revolutions of the Celestial Orbs”) published in 1543

Heliocentric Worldview

• the planets all move in a similar manner

• Heliocentrism

• makes fewer assumptions

• has greater applicability

• the movements of celestial objects can be explained and predicted

Retrograde Mars (and Uranus)Credit & Copyright: Tunc Tezel

But acceptance was slow, asheliocentrism seemed absurd

• If the earth is moving, how can a stone that is thrown straight up come straight down?

• If the earth is a planet, why is it the only one with a moon?

• If the earth did move, why did the relative positions of the stars not (why would space be that big?)

Galileo Galilei

• Born 1564

• Begins studies at University of Pisa in 1581

• 1592 – appointed professor of mathematics at University of Padua

Galileo Galilei

• 1609 – makes his first telescope

• Discovers• Sunspots• Rings of Saturn• Phases of Venus• Satellites of Jupiter

Galileo’s notes of his observations ofJupiter and its moons; January 1610

Galileo Galilei

• Dialogue Concerning the Two Chief World Systems (1633)

• Condemned by the Roman

Inquisition in 1633

• Under house arrest from 1633 until his death in 1642

Galileo Galilei

1979 - Pope John Paul II orders a review of the case against Galileo

1984 - Initial report states that Galileo was wrongly condemned

1989 – Pope acknowledges “imprudent” action of Church

Science as arevolutionary process

“normal” science – sun goes around earth

anomalies – planetos

the “revolution” – earth goes around sun

Another Scientific Revolution

Antoni van Leeuwenhoek(1632-1723)

Some of van Leeuwenhoek’ instruments(replicas)

The first image of microbes (1683)(the dotted line between C and D indicates motility)

Spermatozoa by van Leeuwenhoekoriginally published in

Philosophical Transactions, 1678-9

Van Leeuwenhoek’s Work would ultimately lead to

Robert Koch(1843-1910)

Louis Pasteur(1822-1895)

Joseph Lister(1827-1912)

the discovery that microscopic organisms can cause illness and death

Things to remember

• Scientific discovery is driven by the community of scientists; they actively look for problems with theories

• Scientific discoveries often contradict cherished notions of what the world is like

• Scientific truths are provisional, as better models are continually being pursued

• Science is a self-correcting process