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Transcript of Descartes
The external world exists after all!
Expansion of the C&D rule?
Review: Because God is no deceiver, clear and distinct perceptions are veridical.
Now Descartes appears to expand the class of veridical beliefs to those we have a
to believe (provided we have no faculty with which to correct such judgments).
God is no deceiver
Thus, there is an external world with at least one object in it: God.
God is no deceiver.
Thus, our clear and distinct perceptions are veridical.
Involuntary sensations justification
mind and body are
1. Sensations come to me involuntarily.
2. Therefore, sensations are caused by something external to me.
3. Therefore, there exists something external to me -- an external world.
Not immune from doubt:
Notice, even if the argument were sound, it would not guarantee that the external world is anything like we perceive it.
1. God is no deceiver.
2. Therefore, I can trust what I have a great propensity to believe.
3. I have a
to believe that adventitious ideas are caused by material things.
4. Therefore, adventitious ideas are caused by material things.
Ditto for the judgment that I am awake right now!
Justification for the distinction between mind and body (objective)
clearly and distinctly
perceive that mind and body can be separated (objectively) and C&D perception is veridical (as insured by God).
Taking a closer look at Descartes' metaphysics
We can discover
about the basic structure of reality (how things are in and of themselves) by "withdrawing the mind from the senses" (Med. I) and "see" with the
. That is, perceive what is clear and distinct.
What will we discover?
There are three substances:
God -- essence is perfection
Mind -- essence is thinking
Matter -- essence is extendedness in space (breadth, length, depth); no void!
Hierarchies of existence
Mind & matter ontologically depends for its existence on God, but on nothing else. That is why they are substances.
Modes exist as
of essential and general attributes of substance.
of matter & mind: existence and duration.
of matter: size, shape, position and motion.
of mind: intellect and will.
of thought: pure intellect, imagination, sense perception -- all present to the will & desire, aversion, assertion, denial, doubt.
The mind is really distinct from the body, which means they are different substances. We can doubt the existence of the body, but not that of the mind.
No consensus: did D. view mind & body as possibly formally distinct?
The metaphysical /causal argument for God's existence
Causal Adequacy Principle: whatever is contained objectively (representational content) in an idea must be contained either formally or
* in the cause of the idea.
: that reality is contained in it in a higher form (otherwise God couldn't cause our existence!)
**Implied: Whatever is possessed by an effect must have been given to it by its cause;
something cannot give what it does not have
establishes the formal existence of the mind, but not the formal existence of the body.
... rejected by Descartes.
Note: Some interpreters take D. to switch the standards of knowledge to probability at this point in the Meditations.
God also guarantees that the material world is like I perceive it through the senses.
Suppose I invented the idea of God.
Then I am the cause of that idea.
According to D. I would have to formally or eminently possess whatever is contained in the representational content of God: perfection & infinite substance.
I don't possess perfection formally or eminently.
Hence, I couldn't be the cause of the idea of God; which means God is not a figment of my imagination.