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the first. The major suggestion is that G is necessary
only to validate memoryof proofs. So while you actually clearly and
distinctly perceive something, you do not need to trust anything at
all, even G, to be entitled to assert its truth. But later, when you have
forgotten the proof, only G underwrites your title to say that you
once proved it, so it must be true.

    Other commentators suggest that Descartes does not need the
second. He sees that God exists, clearly and distinctly, but does not
need a general rule, of the kind (C1)p - Tp), to underwrite this
perception. He can be certain of this instance of the rule, without
being sure about the rule itself. This is itself an interesting form of
suggestion, and introduces a very important truth, which is that
very often we are more certain of particular verdicts than we are of
the principles that we might cite when we try to defend them. For
example, I might know that a particular sentence is grammatical,
without being sure of any general rule of grammar that allows it.
Philosophers have often been rather hard on this possibility. The
admired character Socrates, in Plato's Dialogues, is infuriatingly
fond of getting his stooges to say something, showing that they
cannot defend it by articulate general principles, and concluding
that they didn't really have any right to claim what they did. However, the case of grammatical knowledge suggests that this is a bad
inference. Consider as well how in perception, I may recognize
something as a Pomeranian, or a member of the Rolling Stones, or
my wife, without knowing any general principles that `justify' the
verdict. My perceptual system may operate according to some general principles or `algorithms' for translating visual input into verdicts, but I have no idea what they are. So I couldn't answer a
Socrates who asked for general principles underlying my recognition. I could only flounder and splutter. But I recognize the
Pomeranian, or Rolling Stone, or my wife, for all that. Socrates'
procedure is only apt to give philosophers a bad name.
    StiII, we are bound to ask why Descartes thinks he can he certain
of this instance of the rule. Why is his`seeing'that God exists clearly and distinctly also a clear and distinct case of seeing the truth?
Some of us may have the dark suspicion that it is because mention
of God clouds the mind rather than clarifying it.

    For our purposes, we can leave this issue. What remains clear is
that there is a distinct whiff of double standards here.The kind of
sceptical problem embodied in the Evil Demon is somehow quietly forgotten, while Descartes tries to engineer his way off the lonely
rock of the Cogito. And this might suggest that he has put himself
on a desert island from which there is no escape.
    FOUNDATIONS AND WEBS
    The great Scottish thinker David Hume (1711-76) criticized
Descartes like this:
    7iic're is a species of scepticism, antecedent to all study and
philosophy, which is much inculcated by Descartes and others, as a sovereign preservative against error and precipitate
judgment. It recommends an universal doubt, not only of all
our firrrm'ropinions and principles, but also of "our very faculties; o.1-whose veracity, say they, we must assure ourselves, 17y a
chain of reasoning, deduce(! from sortie original principle,
which cannot possibly be fallacious or deceitt id. But neither is
there any such original principle, which has a prerogative
above others, that are sel fevident amt convincing: Or i f there
were, could we advancea step beyond it, but by the use of those
very faculties, of which we are supposed to be already diffident. The Cartesian doubt, therefore, were it ever possible to
beattained byanyhuman creature (asit plainly is not) would be entirely incurable; and no reasoning could ever bring us to
a state of assurance and conviction upon any subject.

    If Descartes's project is to use reason to fend off universal doubt
about the