Descartes

Descartes - b.1596 d.1650 ❑ Not a skeptic – “there really is a world, that men have bodies, and the like (things which no one of sound mind has ever seriously doubted)” ❑ Is he a dualist? ❑ Most people would say so, because of his discussion the mind and the body, yet God is neither mind nor body, so Descartes is something more.

Epistemological vs Metaphysical ❑ Epistemology – study of knowledge. What it is, how we come about acquiring it. ❑ Metaphysics – study of the kinds of things there are in the world.

Epistemological vs Metaphysical ❑ Epistemology – study of knowledge. What it is, how we come about acquiring it. ❑ Metaphysics – study of the kinds of things there are in the world. ❑ Be careful of saying "if we can't know then there is no fact of the matter". That is confusing epistemology and metaphysics. ❑ For instance, depending on what you are saying, you can talk about beliefs and be doing epistemology such as how you acquire them, or you can be doing metaphysics, such as talking about what beliefs are.

Descartes ❑ Foundationalism – pyramid of beliefs ❑ beliefs upon which other beliefs are based ❑ example – the belief that punching people is wrong may depend on beliefs regarding pain and what causes pain. ❑ Descartes sought a firm foundation upon which to base our system of knowledge.

Descartes ❑ Wax example

Descartes ❑ Doubt test – doubt every belief that can be doubted, only then can we be sure that what we are left with is true.

Descartes ❑ Doubt test – doubt every belief that can be doubted, only then can we be sure that what we are left with is true. ❑ Descartes' Application of the Test - systematic, testing each belief individually would take forever, but by examining whole groups of beliefs it becomes possible.

Descartes ❑ Descartes applies the Doubt Test to types of knowledge, testing ones likely to be used as foundations: ❑ Senses ❑ Dream Argument - We could be dreaming right now ❑ Science - if our perceptions do not pass the test, then isn't most of science then necessarily discarded. ❑ Math - could also be wrong if we are being deceived constantly. ❑ Not Dreams ❑ Demon/ Devil / Genius / Genie

Descartes ❑ Why the doubt test? ❑ What better way to ensure that you toss out false beliefs? ❑ You not only toss those you know are false, but ❑ also those which you could be doubted as true.

Descartes ❑ Does the doubt test give certainty? How? ❑ What do we want to say about 'beliefs that can't be doubted'? ❑ are such beliefs necessarily true, meaning that they couldn't be false, or ❑ are we just psychologically unable to doubt them?

Descartes ❏ Passing the Doubt Test ❏ Can I doubt that I think? ❏ Seeming to see, feel, hear - "This cannot be false"

Descartes ❏ Passing the Doubt Test ❏ Can I doubt that I think? ❏ Seeming to see, feel, hear - "This cannot be false" ❏ You are a creature capable of doubt and of thought. In trying to doubt that you prove it to be true that you can doubt. ❏ Could a person doubt that he doubts? No. ❏ Anything else passes? Nope. ❏ In short, having the ability to doubt implies that you have a mind because doubting is a type of thinking.

Descartes ❏ The next task is to begin building from our existence, since the project is to develop a system of knowledge. ❏ What exactly do we have, even given that you know you exist?

Descartes ❏ The next task is to begin building from our existence, since the project is to develop a system of knowledge. ❏ What exactly do we have, even given that you know you exist? ❏ No physical bodies (Might exist, but we can't say if they do)

Descartes ❏ The next task is to begin building from our existence, since the project is to develop a system of knowledge. ❏ What exactly do we have, even given that you know you exist? ❏ No physical bodies (Might exist, but we can't say if they do) ❏ No memory

Descartes ❏ The next task is to begin building from our existence, since the project is to develop a system of knowledge. ❏ What exactly do we have, even given that you know you exist? ❏ No physical bodies (Might exist, but we can't say if they do) ❏ No memory ❏ No time

Descartes ❏ What can we infer from existence as a thinking thing? ❏ Nothing. ❏ We need more. ❏ More = God ❏ A non-deceptive God gives us knowledge of some things. What?

Descartes ❏ What can we infer from existence as a thinking thing? ❏ Nothing. ❏ We need more. ❏ More = God ❏ A non-deceptive God gives us knowledge of some things. What? ❏ God + existence give us un-doubtable useful foundations ❏ What does it take for a foundation to be un-doubtable ❏ God is not un-doubtable ❏ Where do we end up?

Descartes ❏ Questions ❏ Is Descartes’ project of tearing down everything to the foundations a good strategy? ❏ How do we know we aren't dreaming right now? ❏ How do we know we aren't being dreamt? ❏ Would we want to know if we were dreaming? ❏ some deny we could know