Philosophy - Epistemology - Reason as a Source of Knowledge

What is the difference between intuition and deduction?

Intuition is the immediate grasp of a truth by a rational mind, whilst deduction is the gaining of truth through logical reason, built upon knowledge gained by intuitions.

What is Descartes’ definition of clear and distinct ideas?

Clear means that the proposition can be easily grasped by a rational mind and the rational mind will easily arrive to Descartes’ own conclusion, and distinct means that it is so clear that you can differentiate it from other propositions.

How does Descartes define intuition?

A priori (independent of senses) necessary truths that proceed solely from reason in a clear and attentive mind.

How does Descartes define deduction?

Inference following from certain, a priori intuitive truths.

Why is Descartes cogito an example of a priori knowledge?

Because the knowledge that you exist can be gained without any input from the senses/using only logical reason, as to say “I am not a thinking being” requires thinking that you’re not a thinking being.

Outline Descartes’ trademark argument.

He argues that a finite, imperfect being like a human can not conjure an idea of an infinite, perfect God, as something cannot come from nothing and a cause must be as great or greater than it’s effect. He therefore argues that God must have put the idea in humans minds, as he is more powerful than humans.

Outline Descartes’ contingency argument.

Descartes’ could not have always existed, because he would remember as his existence is contingent on him being a thinking thing. He could not have created himself, as he would have made himself perfect. His parents could not have created him, as according to his causal adequacy principle the cause must be greater than the effect. The only rational explanation is that God created him, as He is the sum total of all perfections.

What are the problems with the contingency argument?

Hume’s Fork: Hume says that thinking of something without a cause - like a chair simply appearing into existence - is not logically contradictory like thinking of something like a round square. He also says that there is no actual justification that A causes B, we just see B happen immediately after A millions of times so we have the assumption that A causes B.

Outline Descartes’ ontological argument.

If God is the sum total of all perfections, and existence is a perfection (as not existing is less perfect than existing), then God must exist.

What are the problems with Descartes’ ontological argument?

Gaunillo’s Perfect Island: If Gaunillo can think of a perfect island, and existence is a perfection, then a perfect island must exist. This is extremely improbable and the definition of a perfect island varies from person to person, like the definition of God varies from person to person.

Hume: If ontological arguments succeed, then God’s non existence is a contradiction. However, we cannot conceive of contradictions (like we cannot conceive of a round square), so if we can conceive of a world where God doesn’t exist then non-existence is not a contradiction.

Kant: Descartes treats existence as a predicate (or, a property) of God, but in reality saying that God exists doesn’t add anything to the concept of God. Proving that God exists in the world can only be proven a posteriori.

Why, to Descartes, is the intellect and the imagination different?

The intellect can conceive of things that a person cannot imagine, such as a person can imagine a triangle but not a 1000 sided shape, as well as being able to conceive a 1000 sided shape. He also would not exist without his intellect, but could exist without his imagination.

What is Descartes’ argument for the external world?

God exists, and he is the sum of all perfections and is therefore not a deceiver. Descartes believes, using his senses and experiences, that there is a material world with physical objects that surround him, and since God is not a deceiver, he would not have given Descartes faculties that he could not use to break away from this deception and find the truth, so the material world must be the reality. He also cannot will sensations, so they must come from the material world or something else outside of him.

What are the weaknesses of Descartes’ argument for the external world?

• Dreams are not part of someone’s will, but they happen internally anyway

• It isn’t clear and distinct that a human can create an extended idea, as they can process them

• God might be feeding us sensations instead of there being a material world that exists independently of God

• We can be deceived by senses, so maybe God is indeed a deceiver OR is deceiving us for our own good

• God simply might not exist