Meditation IV

Now, we know God exists. But what if he is out to deceive us?

"it is impossible for God ever to deceive me, for trickery or deception is always indicative of some imperfection. And although the ability to deceive seems to be an indication of cleverness or power, the will to deceive undoubtedly attests to maliciousness or weakness. Accordingly, deception is incompatible with God." (81)

Why should we say that the presence of 'the will to deceive' is a sign of weakness?

Consider: if I deceive you then I either do it in order to fool you or else to spare you finding out some truth.

 
But, if I need to fool you it seems I must need something from you. How is that possible if I am all powerful?

And if I were all powerful, I wouldn't need to lie to you to stop you finding out this truth, I'd just see to it that it wasn't a truth.

 The Problem of Error: "it seems to follow from this that I am never capable of making a mistake. …[but] I am subject to countless errors." (81-82)
How can we solve this problem?
Strategy: Show that the errors we make cannot be blamed on God.

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First Attempt: "error as such is not something real that depends upon God, but rather is merely a defect." (82)

It's not a presence, it's an absence. But "No doubt God could have created me such that I never erred." (82)
Can't we therefore blame him for not doing a better job at building me?
Second Attempt: Maybe there's a good reason why I am built this way. "there is no reason to marvel at the fact that God should bring about certain things the reasons for which I do not understand." (82)

Don't Look for Final Causes:

 
God "can make innumerable things whose causes escape me. For this reason alone the entire class of causes which people customarily derive from a thing's 'end,' I judge to be utterly useless. It is not without rashness that I think myself capable of inquiring into the ends of God." (82)

This is a dig at the Aristotelian tradition in which much emphasis is placed on understanding the purpose of things. Descartes thinks science is all about understanding how thinks work, not what for.

 Third Attempt: Errors arise from the improper use we make of the faculties God has given us. If we used them as we were supposed to, we wouldn't go wrong.
The Source of Error: "errors depend on the simultaneous concurrence of two causes: the faculty of knowing that is in me and the faculty of choosing, that is, the free choice of the will" (83)
The Understanding: My understanding may be limited, but that doesn't reflect badly on God. "I cannot adduce an argument to prove that God ought to have given me a greater faculty of knowing than he did." (83)

The Will: "I experience that it is limited by no boundaries whatever." (83)

"the will is the chief basis for my understanding that I bear a certain image and likeness of God." (83-4)   "God's faculty of willing does not appear to be any greater." (84)   "when something is proposed to us by our intellect, either to affirm or deny, … we are moved in such a way that we are determined to it by no external force." (84)

What is free will? In making a decision, "the more I am inclined toward one direction – either because I clearly understand that there is in it an aspect of the good and the true, or because God has thus disposed the inner recesses of my thought – the more freely do I choose that direction." (84)

 
Is this a plausible account of free will?
The Source of Error (Again): "They [i.e., errors] are owing simply to the fact that, since, the will extends further than the intellect, I do not contain the will within the same boundaries; rather, I also extend it to things I do not understand." (84)

How to avoid error: "if I hold off from making a judgment when I do not perceive what is true with sufficient clarity and distinctness, it is clear that I am acting properly and am not committing an error." (85)

Getting God off the hook: "it is surely no imperfection in God that he has given me the freedom to give or withhold my assent in those instances where he has not placed a clear and distinct perception in my intellect." (86)


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Summing Up: Now, we are supposed to have shown that God exists and he's not a deceiver. As a result, we can rely on the standard of clarity and distinctness. We thus have a method we can use to rebuild our knowledge.

Is this convincing? The Cartesian Circle Many people think there's a fundamental flaw in Descartes' reasoning.

1. The Cogito gives us a criterion of truth. What we clearly and distinctly perceive is true. But, we can only count on this standard, if we can rule out deceit by the Evil Demon (or whatever).

2. We can rule out massive deceit if we can prove God exists and is not a deceiver.

3. We use principles we clearly and distinctly perceive to show that God exists and is not deceiver. (E.g., "it is evident by the light of nature that there must be at least as much [reality] in the … cause as there is in the effect of that same cause.")

4. Therefore, we can trust the standard of clarity and distinctness.

 What fallacy does Descartes seem to commit if this sketch of his reasoning is accurate?

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Implications of the Cartesian Circle:

1. If Descartes is wrong, he may be helpfully wrong.

Can we do any better than he does? If not then perhaps what we learn from him is that there's very little we can be certain of. 2. What if he does fail? How bad would this be? Can't we just say 'okay, so we're not certain of much. Big deal'? Maybe not: Certainty and Knowledge
  P1: If you know you're in class right now then you know you're not a brain in a vat being deceived by a mad scientist/evil demon/travelling salesman/...

P2: If you're not certain you're not a brain in a vat then you don't know you're not a brain in a vat.

P3: You're not certain you're not a brain in a vat.

P4: You don't know you're not a brain in a vat. (from P2 and P3)

C: You don't know you're in class right now. (from P1 and P4)

  Can't we repeat this argument for almost anything we might claim to know?

If so, then as goes certainty, so goes knowledge. Skepticism, more or less, turns out to be correct.

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3. Descartes might still achieve something impressive.

From the Fifth Meditation: "even if not everything that I have meditated upon during these last few days were true, still the existence of God ought to have for me at least the same degree of certainty that truths of mathematics had until now." (89)

That is, we can be as confident that God exists as we are that 2+2=4. Both are only open to the 'evil demon' level of doubt. That's a pretty remarkable achievement if he pulls it off.

 [Philosophy 1200]