© Michael Lacewing

Plato and Hume on Human Understanding

Michael Lacewingenquiries@alevelphilosophy.co

.uk

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!

On the Good

• Plato: What gives truth to the things known [the Forms] and the power to know to the knower is the Form of the Good.– What is the Good?

• Hume: there is no knowledge of the good. Morality isn’t about truth, but about feeling.