Download - © Michael Lacewing Plato and Hume on Human Understanding Michael Lacewing [email protected]
The two camps
• Rationalism: we can have substantive a priori knowledge of how things stand outside the mind.
• Empiricism: we cannot.
‘A priori’ and ‘analytic’
• A priori: knowledge that does not require (sense) experience to be known to be true (v. a posteriori)
• A proposition is analytic if it is true or false just in virtue of the meanings of the words.
Plato’s rationalism
• We have a form of rational ‘intuition’ or ‘insight’, nous, which allows us to grasp certain truths intellectually (after a lot of training!).
• Sense experience cannot give us knowledge, only reason can.
• Our concepts are derived from, or imperfect reflections of, the Forms, which are only known through reason.
The Forms exist independently
• Good things are not the same as goodness (Form of the Good).– If all good things were destroyed, this
wouldn’t destroy goodness itself.
• Forms don’t exist in any particular place or time.
• Forms don’t change.• Forms are perfect examples (nothing is
more good than goodness itself).
Against empirical knowledge
• All objects of experience are particular things.
• All particular things are both one thing, e.g. large, beautiful, good, and the opposite.
• If something is both X and not-X, then we can’t know that it is X.
Knowledge of the Forms
• Particular things are what they are only relatively and transiently; knowledge is certain and permanent.
• The Form of beauty is pure beauty; it (alone) is not both beautiful and not beautiful.
• The Form of beauty is beautiful under all conditions, to all observers, at all times.
• Therefore, we can have knowledge of the Forms, though not through our senses.
Hume’s fork
• We can only have knowledge of – Relations of ideas– Matters of fact
• Relations of ideas are a priori and analytic
• Matters of fact are a posteriori and synthetic
• Reason doesn’t do ‘insight’.
Origins of concepts
• All ideas are ultimately derived from impressions – something that occurs in our experience.
• We can form complex ideas for which we have no corresponding impression. But all such complex ideas are derived from simple ideas, which are copies of impressions.
On reason
• Hume to Plato: What is ‘nous’? How does it provide knowledge?
• Plato to Hume: Hume shows how limited empiricism is. Without nous, we fall into scepticism.
On knowledge
• Even if knowledge cannot change, that doesn’t mean the object of knowledge can’t change:– I can know the size of this handout
now, even if the handout changes later.
– Plato has confused a property of knowledge for a property of the object of knowledge.
On certainty
• Plato sets the standard for knowledge very high (certainty).
• Hume seems to accept this - we only know immediate sensation, deductive reasoning, and analytic truth
• So they both agree we can’t have knowledge of physical objects!