Meditations on First Philosophy — Descartes

Deliberately doubting everything that can be doubted, so that whatever survives must be certain.

The senses deceive → the dream argument (can't prove you're awake) → the evil demon (could fake even maths).

Dreams feel just as real as waking, so you can't be certain you're awake — even ordinary beliefs wobble.

An imagined all-powerful deceiver used to doubt even simple truths like 2 + 3 = 5 — the hardest test for certainty.

A belief that cannot possibly be false — not just likely, but immune even to an all-powerful deceiver.

No — he uses doubt as a tool to rebuild knowledge on certain foundations, not to abandon it.

It's a deliberate, pretended doubt used as a filter — not a real loss of belief.

Tip out every apple and only return the sound ones — that's Descartes clearing beliefs to keep only the certain.

'I think, therefore I am' — even a deceived mind must exist to be deceived, so a thinking thing certainly exists.

To doubt it you must think, and to think you must exist — so doubting it proves it.

Only that you are a thinking thing (a mind) — not that you have a body or that the world is real.

A 'thinking thing' — a mind that doubts, believes, wills, imagines and senses.

It's the first belief to survive the evil demon, so all rebuilt knowledge stands on it.

Yes — the act of doubting it is itself thinking, which proves a thinker exists.

It proves existence only in the present moment of thinking — not that you existed yesterday or will tomorrow.

The cogito proves a mind exists; the body is still doubted and only recovered much later.

Mind and body are two really distinct kinds of thing: the mind thinks, the body is extended.

The mind — a thinking, unextended thing (it doesn't take up space).

The body — an extended, physical thing (it takes up space but doesn't think).

Heat the wax and every sensed quality changes, yet you judge it's the same wax — so the mind, not the senses, grasps what it is.

The mind grasps what things truly are, and so is even better known than the body.

I can clearly conceive mind without body and body without mind, so God could make them exist apart — they're two things.

Being able to CONCEIVE them apart may only show they seem separable, not that they really are (Arnauld's worry).

You HAVE a body (extended) but you ARE a mind (thinking) — the mind is what you essentially are.

The cogito proves only his mind; a non-deceiving God is needed to rule out the demon and restore the world.

My idea of a perfect being is too great for imperfect me to have made, so a perfect being (God) must have caused it.

The idea of perfection is stamped in us by our maker, like a craftsman's mark on their work.

A perfect God won't deceive, so my strong natural belief that an external world exists can't be a lie.

Ideas so sharp I can't doubt them while attending to them — a non-deceiving God guarantees they're true.

Deceiving is a defect, and God is all-good, so God is no deceiver — the key premise for the rebuild.

Cogito → God exists → God is no deceiver → clear ideas are true → the external world is real.

He uses clear ideas to prove God, then uses God to guarantee clear ideas — the system's biggest objection.

Test the reasoning of a claim — weigh reasons for and against — and reach a reasoned judgement.

Descartes proves God from clear and distinct ideas, then uses God to guarantee clear ideas — apparent circularity.

Maybe God is only needed to trust MEMORIES of past clear ideas, not present ones — softens but may not remove the circle.

If the mind is unextended and the body physical, how can one move the other? Raised by Princess Elisabeth.

The method of doubt and the cogito largely hold; the God-proofs and the rebuilt world are the weakest links.

Open-book, one hour: a two-part question on your text — (a) Explain a concept [10] + (b) Evaluate a claim [15].

Don't copy long quotes — use the text to SUPPORT understanding and argument; do the right job in each part.

Explain the claim, argue for it, raise the objection, weigh them, and conclude with a reason tied to the text.