PHIL 202 Lecture Notes - Lecture 6: A Priori And A Posteriori, Empirical Evidence, Pure Mathematics
4 May 2018
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History of Modern Philosophy
2.02.18 Lecture Notes – Descartes, Fifth Meditation
- Fourth Meditation: guarantee of infallibility
- The goal of the Fifth Meditation is to lay down certainty for material objects
- Method is to consider ideas before looking at the material objects
o Still locked in his mental state
- Quantity or continuous quantity
o All of Cartesian science is the science of quantity
o Quantity kind of interchangeably used with extension
o Everything has extension
o His physics – wants to give a mechanical explanation (physical objects and
physical forces; given in terms of matter and motion)
▪ Scholastic philosophers had attributed to objects almost magical
properties so Descartes is distancing himself from this tradition
- Example of the triangle
o The idea of the triangle cannot be invented by him
o Must have certain properties that must be attributed to a triangle
o Some ideas have very determinate properties (like an exact definition)
o Clear idea of the triangle (remember that every clear and distinct perception is
undoubtedly something)
o The triangle must be something
o Result: he can cross off himself as the source of the triangle
- Ideas can be innate, adventitious, and inventions
o The triangle cannot be an invention
o Perhaps the idea of the triangle comes from experience (empiricist view)
▪ Argument against the empiricist view?
▪ We can conceive of a 1000-sided figue ut e’e ee epeiee it!
▪ So, our ability to imagine these shapes comes from something innate and
not something external because we can
- His first argument for God – causal adequacy argument
- His second argument in this meditation
o Perfection includes existence so God must exist by definition
- End of 4th
o Clear and distinct ideas must be about something --- because God has made it
that way
o Usig this lea ad distit idea to poe God’s eistee
o Is this circular?
- We’e osideig the ideas of ateial thigs
o His physics will be an a priori physics
o A Pioi: ou ko it’s tue o false ithout efeig to the world or sense
experience
o A priori physics – trying to give the metaphysical foundations for his physics
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Document Summary
The goal of the fifth meditation is to lay down certainty for material objects. Method is to consider ideas before looking at the material objects: still locked in his mental state. His first argument for god causal adequacy argument. His second argument in this meditation: perfection includes existence so god must exist by definition. End of 4th: clear and distinct ideas must be about something --- because god has made it that way, usi(cid:374)g this (cid:272)lea(cid:396) a(cid:374)d disti(cid:374)(cid:272)t idea to p(cid:396)o(cid:448)e god"s e(cid:454)iste(cid:374)(cid:272)e. Cogito certainty about my own existence god"s e(cid:454)iste(cid:374)(cid:272)e certainty about everything else (physics: the metaphysical foundations for everything else or his physics. Some of the stuff coming out of his physics: body as extension, concept of motion, laws of nature. When he is attending to the proof of maths, he has a justification, but when he is not attending, he seems to lose the justification: then makes a strong claim about memory.
