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Robert J. Yanal *
"Knowledge is in the end based on acknowledgement."
Ludwig Wittgenstein, On Certainty 1
In his Meditations Descartes tells us that he initially thought error might be avoided if he withheld assent "no less carefully from what is not plainly certain and indubitable than from what is obviously false." For example, he thinks it plainly certain and indubitable that he is "sitting by the fire, wearing a winter cloak, holding this paper in my hands, and so on." And yet even what is "plainly certain and indubitable" can be doubted. "I will suppose, then, not that there is a supremely good God, the source of truth; but that there is an evil spirit, who is supremely powerful and intelligent, and does his utmost to deceive me." Such a deceiver can spin illusions that appear indubitably real and true--of hands, fire, cloak, paper--and not only when there are none present in any particular case but even where there are none at all in any case. "I will suppose that sky, air, earth, colors, shapes, sounds and all external objects are mere delusive dreams, by means of which he lays snares for my credulity." 2 The deceiver hypothesis is the most difficult skeptical doubt Descartes must surmount in the remaining Meditations.
I say the deceiver hypothesis, and for Descartes the deceiver is a mere possibility, raised so as to motivate the reconstitution of knowledge that follows. That there might be a powerful deceiver is itself a threat to knowledge for Descartes. Indeed even the possibility of an evil deceiver is so powerful a threat that Descartes must do nothing less than prove God's existence to reestablish certainty. It is only at the end of his Meditations that Descartes can say, as if looking back on a hysterical moment, that the evil deceiver idea was "exaggerated" and "ridiculous." 3 [End Page 67] But might not deceivers be real and not just possibilities? And might these real deceivers be anything but exaggerated and ridiculous?
Descartes's cosmically deceptive genius is inconsistent with God's existence. But real deceivers who hide or distort the truth now and again on certain matters are a fact of life--as consistent with God's existence as dreams. This is not a skeptical hypothesis but a simple observation. Illusionists, con men, and seducers have deceived multitudes. These are professional liars, but even people in positions of trust can act as deceivers--husbands, employers, housekeepers. One can even deceive oneself. Such deceivers may not be able to make you think there are external objects when in fact there are not, though they may have the power to trick you in other ways. We might say that the existence of ordinary in-the-world deceivers makes plausible a skepticism about a certain delimited realm. Affairs of the heart is just such a realm. Such a skepticism seems neither exaggerated nor ridiculous but a commonplace of life.
Descartes's evil deceiver works in a fairly specific and powerful way. He offers false perceptions--hallucinations, really--that seem true. There are other deceptive possibilities. A deceiver can make what is true appear to be false. Or the deceiver can keep us from the truth not by making what is true seem not to be, but by disabling our faculty of judgment, rendering us so cognitively enfeebled that we cannot arrive at a judgment though we may be in possession of sufficient evidence. Or a deceiver can withhold information and thereby let us draw a conclusion that is not true, a conclusion we would not have drawn had we had fuller information. Or a deceiver can make us leap to conclusions, taking scant evidence and inflating it in our minds so that we think we know when we don't. Or a deceiver can lure us into ignoring evidence so that we think we don't know when we do.
Alfred Hitchcock in his first American film, Rebecca (1940), explores the idea of deceit and of deceivers who inhibit knowledge, specifically the heroine...