31 January 2001
I. Review: Problem of Evil
A. Impossible to remove evil without making things
worse?
B. Maybe now; but is this the best
possible overall plan?
II. Epistemology (=Theory of Knowledge)
A. What is knowledge? Is it possible? Do we have it? How? Under what conditions?
B. Knowledge = justified true belief?
III. The
“method of doubt” in Meditation I
A. Epistemic overhaul
B. Dreaming argument
C. Extent
of conclusion of dreaming argument?
D. Evil
demon hypothesis
The Dreaming Argument
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(1) Belief in the
existence of ordinary physical objects is based on sensory experience. |
“Whatever I have so
far accepted as supremely true, I have learned through…the
senses.” |
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(2) It sometimes seems
(when one is asleep and dreaming) that one is sensing ordinary physical
objects when in fact one is not—that is, apparent sensory experience
can be mistaken. |
“As if I can’t remember
having been deluded by similar thoughts while asleep!” |
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(3) If there are no
reliable signs by which to distinguish being asleep from being awake, then
one can never be sure whether some apparent sensory experience is mistaken. |
Premise |
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(4) There are no reliable
signs by which to distinguish being asleep from being awake. |
“…I see so
plainly that there are no reliable signs by which I can distinguish sleeping
from waking….” |
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(5) One can never be sure
whether some apparent sensory experience is mistaken. |
From 3 and 4 |
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(6) If one can never be
sure whether some apparent sensory experience is mistaken, then one can
reasonably doubt the existence of ordinary physical objects. |
Premise, uses 1 |
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Therefore, (7) One can reasonably
doubt the existence of ordinary physical objects. |
From 5 and 6 |
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