Philosophy: Basic Questions; Prof. Boedeker; handout on Descartes #1
Meditation I: Rational doubt
A. Knowledge:
Definition 1 (“knowledge”): I know that p = I know that p is ___________________
true
From Def1, we can conclude:
C1: If p is not certainly true, then I ___________________ know that p.
Def2 (“certain truth”): p is certainly true = there’s no good reason that p might be
___________________
From Def2, we can conclude:
C2: If there is a good reason that p might be false, then p is _____________ certainly
true.
From C2 and C1, we can conclude:
C3: If there is a good reason that p might be false, then I ___________________
know that p.
B. The method of doubt: C3 gives Descartes a ___________________ for eliminating those
of his beliefs that he doesn’t really ___________________. All he has to do to show that he
___________________ know a class of beliefs is to show that there’s a good reason why
those beliefs might be ___________________. Note that this is a much easier task than
showing that these beliefs ___________________ false.
C. Applying the method of doubt to classes of beliefs:
1a. Class of beliefs (1): The exact testimony of the senses, i.e., that things are just as they
___________________ to the senses.
1b. Reason to doubt beliefs (1): I have made perceptual ___________________ in the
past, and I don’t know that I’m ___________________ making a similar perceptual
error ___________________.
2a. Class of beliefs (2): The (physical) objects that seem to be given to me through my
senses ___________________ (even though they might not be just as they appear).
2b. Reason to doubt beliefs (2): I have been misled to believe in existence of the really
non-existent objects of my ___________________, and I don’t know that I’m not
_________________________ now.
3a. Class of beliefs (3): Purely intellectual matters (such as _______________________)
are just as they seem to my mind when I clearly and distinctly perceive the
___________________ involved (thus, for example, not when I’m just being
___________________).
3b. Reason to doubt beliefs (3): I ___________________ know that my mind and all of
my experiences weren’t created by an evil ___________________ (i.e., an omniscient,
omnipotent, but malevolent ___________________). Being evil, this genius might want
to deceive me by making intellectual matters that I clearly and distinctly perceive
___________________ true to my mind, whereas they were in fact
___________________. (Thus, for all I know, 1 + 1 really might ___________________
equal 2.)
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Meditation II: Descartes’ first certainty
A. Descartes’ of knowledge also give him a way to recognize what, if anything, he actually
___________________.
From Def1 and Def2, we can conclude:
C4: I know that p = I know that there’s no good reason that p might be
___________________
And from C4, we can conclude:
C5: If I know that there’s no good reason that p might be false, then I know that
____________.
Thus if Descartes can discover something for which there’s no good reason why it might
be ___________________ – i.e., something that can’t be rationally
___________________ – then Descartes knows that it must be ___________________.
B. So what is this first certainty?
P1 (“principle of the substantiality of thought” = “I think; therefore I am” = “cogito
ergo sum”): If I engage in a mental act, then it follows logically that I
___________________ as a thinking mind.
P2: _______________________ that p is engaging in a mental act.
From P2 (substituting “I exist” for “p”) and P1 (substituting “I doubt that I exist” for “I
engage in a mental act”), we can conclude:
C6: If I doubt that _______________________, then it follows logically that I
_______________________ as a thinking mind.
P3 (“principle of the transparency of thought”): If I engage in a mental act, then I
_______________________ that I engage in that mental act.
From P2 (again substituting “I exist” for “p”) and P3 (substituting “I doubt that I exist”
for “I engage in a mental act”), we can conclude:
C7: If I doubt that I exist, then I _______________________ that I doubt that I exist.
P4 (“principle of closure”): If I know that q, then I know everything that follows
_______________________ from q.
From P4 (substituting “I doubt that I exist” for “q”), we can conclude:
C8: If I know that I doubt that I exist, then I know everything that follows logically
from my doubting that ______ _________________.
From C8 and C6, we can conclude:
C9: If I know that I doubt that I exist, then I know that I _______________________
as a thinking mind.
From C7 and C9, we can conclude:
C10: If I doubt that I exist, then I _______________________ that I
_______________________ as a thinking mind.
C10 entails that I know that there’s no good reason to _______________________ that I
exist as a thinking mind. Thus from C10 and C5, Descartes concludes his first certainty:
C11: I know that I _______________________ as a thinking mind.
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Meditation IV: Error
A. What is responsible for my errors?
P1: If I’m forced to err, then God – my creator – ___________________ me.
P2: A deceives B only if A is either _______________________,
_______________________, or ________-_______________ .
P3: God is _______________________ (= omniscient, omnipotent, and
[omni]benevolent).
From P2 and P3, we can conclude:
C1: God does not _______________________ me.
From P1 and C1, we can conclude:
C2: I’m not forced to ___________________.
P4: If person P does action A, but P is not forced to do A, then P does A out of P’s
metaphysically ____________ _______________.
From P4 (substituting “I” for “P” and “err” for “does action A”) and C2, we can
conclude:
C3: When I err, I do so out of my metaphysically _____________ ______________.
Error is thus an _______________________ of our metaphysically free will to make
_______________________ judgments – i.e., to judge false ideas to be true.
Thus judgment (=_______________________) is a function of the metaphysically free
will.
B. How to avoid errors: the principle of clear and distinct perception:
P5: If there’s any idea that I clearly and distinctly perceive, then I’m
___________________ to judge it to be ___________________.
From P5, we can conclude:
C4: If there’s any false idea that I clearly and distinctly perceive, then I’m forced to
judge a ___________________ idea to be true.
Def1 (“mistake”): I make a mistake = I err = I judge a _______________ idea to be
______________
From Def1, we can conclude:
C5: If I’m forced to judge a false idea to be true, then I’m forced to
___________________.
From C5 and C2, we can conclude:
C6: I’m _______________________ forced to judge a false idea to be true.
From C4 and C6, we can conclude:
C7: There’s no __________________ idea that I ___________________ and
________________________ perceive.
From C7, we can conclude the principle of clear and distinct perception:
C8: Every idea that I clearly and distinctly perceive must be __________________.
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In giving me the ability to judge only those ideas that I clearly and distinctly perceive,
God has given me the ability ___________________ to make errors.
I _________________ my __________________ when I judge something true that I
don’t clearly and distinctly perceive.
This gives Descartes a method for never making an _______________________:
Never judge an idea _______________________ unless you clearly and distinctly
perceive it.
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