Monday, January 17, 2011
• Find that he can doubt the existence of anything, but his own existence beyond
doubt; thought proves existence therefore undoubtability proves truth
• Found out own existence by ratiosynation rationalist
• You always know what experiences you’re having
• The way in which he exists is as something that has thoughts; he is a thinking
• Teaches him the physical world around him is not known to exist by him. He as a
thinking thing is a property that is known to him. His mind differs in property
than his brain. Proves metaphysical dualism (mind is different than the body)
• More certain of what occurs in own mind than what occurs outside (mind over
body). Knowledge of his mind and not the world around him.
Descartes knows his mind is a thing – a mental substance
• Mind can expose itself to itself – creating ideas of all different kinds of things
there are. Mind is aware of itself opposite of the body; doesn’t have length,
width, dimensions, etc.
• Depiction – resembles the thing that is its cause
• Worried things that cause him to have experience aren’t what they actually
resemble – could be tricked by an evil demon, experiment, etc.
• Causal relation between physical stuff in the world/brain and the mind –
representational theory of the mind (mind is aware of the world only through a
Classifies things in his mind:
• Substances, Modes of Substances, Infinite Substances
o Substance – power to exist on its own, even if nothing else existed
o Properties – can only exist by something having that property (ex.
property of being red. Can’t think of redness without something being red)
o Infinite Substance – Power to bring about its own existence, always
existed so it didn’t need to be brought up (i.e. God)
• Rate of reality: (highest) Infinite -> Substances -> Properties (lowest)
How did he get these ideas?
o Got in his mind by being caused by what the ideas resemble; accurate
pictures of the world around him
o Defects in his sense organs, insanity, tricked, etc.
Intuitive to think A can cause a change in B if A is at least as real as B (i.e. A as real or
powerful as B if it has or could have any property B could have; everything equally real
or powerful) Mind has the power to think of any idea of which it could have the properties (i.e. mind
could think up the idea of a door because it could have the properties of a door).
Could the mind be infinite?
• If it was infinite, Descartes would be all knowing
• Cannot make something finite into something infinite. Descartes finite self does
not have the ability to be infinite – means there would be some day in which the
transformation from finite to infinite would be complete
• Infinite thing would have to come somewhere other than Descartes mind
• Can’t teach infinity by observation, can’t dream it up.
• Born with the concept of something infinite?
• If there is an idea of God, he couldn’t have thought of it himself, because the
mind can’t think of the infinite
• God created Descartes with his senses
• God had a choice – Descartes with unreliable senses (wouldn’t do that, be the
same as lying to him. God would be perfect; no morally perfect being would lie.
Descartes now knows that his senses must be accurate. “There’s the table, or
God’s a liar.”) Descartes just needs to open his eyes and knows that his
observations are accurate. God = accuracy of senses of the world to Descartes
• Why do I make mistakes?
o If God’s going to create a physical being, physical beings must have
limits. Nature of the operation of our senses as physical observation
apparatuses. Senses = limited
o God gave Descartes an unlimited capacity to make observations
o Power of freedom of choice of belief
o When Descartes makes mistakes, it’s because he makes beliefs beyond his
o If careful, senses will never lie.
• Even though there is a physical universe, the mind is not part of it, it is a non-
• Knows mind better than physical objects
• Thinking = brain waves
• Descartes thinks this cannot be true
• If A is the same object as B, A has all the same properties of B. If A and B have
different properties, they are not the same object
• Mind and brain have different properties, therefore they must be different objects
(mind is infallible, well-known, brain is not)
• We can imagine the possibility of surviving the death of our brain -> going to
• Mind = brain, then you couldn’t imagine that • If the brain disappears, then the mind would be destroyed too
• We can imagine the mind existing even if the brain does not
• Therefore it follows that the mind and brain are separate objects
• Mind connected to the brain
• Mind has experiences of the world from the brain sending signals of the outside
• Descartes thought the body was 2 objects: Biological Machine and a Ghost
• If God designed all this, why do I make mistakes? Body-mind connection =
imperfect (ex. sensation in body caused by something else in the body)
• Does this mean God is deceiving you? No. He is providing the best possible
connection using the sensory apparatus he’s given you
It’s possible that there’s an evil demon and therefore I have reason to doubt something.
You have reason to doubt something if you have actual evidence (i.e evidence of an
actual evil demon).
The mere fact that something is possible doesn’t mean you need to worry about it.
• Evidence that our senses sometimes deceives us
• Descartes proves his judging is unreliable and uses his judgment in his
• You only know something is you prove it beyond a doubt
o Descartes did not prove
• If it’s possible that your mind that can survive the death of your brain, then it
must be possible that your mind is not your brain. It does not follow that it must
be the same thing as your brain
How can there be a causal relation between mind and body? Physical vs. non-physical
Locke: Locke thought to prove things with primary qualities. Senses made up by the
mind (sight, smell, sounds, etc.) Secondary properties only exist in the mind, but likewise
do the primary qualities
Barkley: Each of us had an experience of the world in their mind. What makes an idea
true is whether it fits the idea in God’s mind
Kant: Believes no way of conceiving an object except how it’s presented to us. What
would a thing be like on its own? Wouldn’t make sense. Royce: Agrees, but we’re all apart of a big mind, namely God’s mind.
• Royce believes only the mind exists
• If all that exists is the mind, self-luminous (can’t be wrong in itself), power to
know everything there is to know – solves the problem of skepticism.
• Explains a relation between mental things and physical things – same things –
namely, the same kind of mental thing. Don’t need a touchable thing and an
• Laws of non-touchable in the mind as root fact – dualism, skepticism go away
• Get rid of the physical world gets rid of the problems
We are familiar with nothing but ideas in our own mind, everything else is a construction.
No physical world; hypothesi