1. God is not a Deceiver, Truth Criterion & Problem of Error
Meditation IV
God is not a Deceiver, Truth Criterion & Problem of Error

2. Proving Everything I Clearly and Distinctly Perceive is True
1) I lack any faculty whereby to discover anything I clearly and distinctly perceive to be mistaken.
2) God would be a deceiver if, lacking such a faculty, my nature was in fact so defective that I tended inexorably to error and illusion.
3) By the conclusion of the proof that God is not a deceiver, it follows that it is impossible that I am by nature prone to error (i.e. the metaphysical doubt grounded on the malicious demon hypothesis is refuted).
4) Since the only ground I had for doubting things I clearly and distinct perceive (i.e. intuitively and demonstratively apprehended propositions of logic, mathematics, and metaphysics) is now removed, it follows that everything I clearly and distinctly perceive is true.

3. 1st Proof that God is Not a Deceiver
1. The will to deceive is evidence of malice or weakness on the part of the deceiver.
2. Malice or weakness are imperfections (are bad making, not good-making).
3. Therefore, any deceiver is imperfect.
4. God is maximally perfect (has no imperfections).
∴ God is not a deceiver.

4. Consequences of the 1st Proof
The First Problem of Error: The “Overproduction” Problem
Given what has already been established, i.e., that i) God exists, and ii) God created my faculty of judgment, and iii) is not a deceiver, I should never make errors in judgment.
But I do.
Therefore, the proof proves too much.

5. Revised Proof that removes Overproduction Problem
1) From the supreme being only being may flow (non-being - nothingness - neither needs nor can have a cause).
2) As finite and limited, creatures (created beings) consist of non-being as well as being.
3) Only the being of creatures can derive from God, not their non-being.
4) Truth is the being of knowledge, falsity (ignorance) its non-being.

6. 5) Falsity can never flow from God, never be caused by God.
6) As the cause both of my essence and my existence, God cannot be the cause of my errors.
7) Therefore, God does not deceive me; and by similar reasoning, we may clearly and distinctly perceive that no being is ever deceived by God.
Notice: #6 flatly denies what the overproduction problem asserts: that God is the cause of my errors.

7. The Second Problem of Error
“Error is not a pure negation, but rather a privation or lack of some knowledge which somehow should be in me.” -- RD
Descartes’ worry: if errors in judgment are privations, then God, while not responsible for creating these errors, seems nonetheless responsible for a failure to give me some knowledge I could have had, and thus has given me an imperfect faculty of judgment.
Why this is a problem: because God, being perfect, cannot create anything imperfect.

8. RD considers two initial ways one might solve this problem: 1) at God might have reasons for making us imperfect in judgment, but that given God’s infinite perfections and powers, these reasons could be beyond our comprehension. 2) that while we may seem imperfect in our acts of judgment that involve errors, the overall perfection of the world is served by these errors. These two solutions seem to be proposed and then immediately abandoned in favor of another approach, one that hinges on showing that God did not fail to make me perfect in my faculty of judgment, even though I make errors with it. This solution depends on noticing something that has been missed so far

9. My faculty of judgment is not one mental power but two!
My faculty of judgment is a combination of two powers acting in concert:
1) a power of intellect (the power to combine concepts into the form of a judgment)
2) a power of will (the power to commit myself to the belief contained in the judgment--the means by which a judgment becomes an assertion)

10. How this solves the Second Problem of Error
If each of the two powers of mind that constitute my faculty of judgment are each perfect in themselves, then God has not, though perfect her/him/itself, created something imperfect in me.
Descartes then argues that the intellect and will are each perfect powers.
1) The intellect is perfect because it is simply the power to grasp ideas and to combine them in judgments, and in each of these capacities, the intellect shows no defect [there are no ideas we have that we cannot combine with any others], and all ideas we do grasp are grasped (which is all that is required to be a faculty-of-grasping-ideas)

11. 2) The power of will is perfect, since all a will is for is to make choices and our will is entirely unfettered in its capacity to choose (in this, our will is no less perfect than God’s).
The real cause of errors in human judgment:
3) We extend our will beyond the scope of our intellect, which is limited (it only grasps a subset of all the possible ideas pertaining to all the realities contained in the world, and thus is only capable of finite knowledge of the world) and thereby, commit ourselves to assertions that are in error.

12. How to Avoid Errors in Judgment: Restrict our will to the scope of our intellect What this means in practice: Refrain from committing to any beliefs that could possibly be in error. How we can do that: Only commit to beliefs that satisfy the truth criterion, since this ensures the truth of the judgments we do commit to.

13. Is Descartes now Through with the Problem of Error?
Nope......He now considers reasons for continuing to think God has somehow failed to act from a godly and perfect good will by creating human beings with a two-power faculty of judgment that, for those that have not read The Meditations, will allow us to make errors in judgment.

14. Continuing Reasons for Unhappiness with RD’s Solution
1. Although God has not failed to act in accordance with godly perfection and good will by making human minds capable of error, surely God could have made us smarter, and if so, since God is supremely good, and our being smarter would make our lives better, in making us less smart God has failed to act from perfect goodness. God could have made me incapable of thinking anything that involves intellectual error, and in not doing so, has a responsibility for the errors I do make.

15. Descartes’ Reply:
We couldn’t have unlimited intellects, since if we did, we would be God, and there can only be one of those (RD does not say this in Med. IV, but it is the reason for what he does say, which is that we, as created beings, must necessarily be limited.
Rejoinder: but that still does not explain why we are limited precisely at the level we are nor why God did not make us incapable of these mistakes (i.e., the mistakes we actually do make).

16. Descartes’ Reply:
While if I were incapable of thinking what is false, I would certainly be more perfect than I am, I cannot know whether the world as a whole is more or less perfect with creatures who, like myself, are not immune from error (and notice: in order to settle this question, I must understand what would determine the overall goodness of the entire world, something that exceeds my finite intelligence)
Furthermore, what good reason do I have to complain that God has not made me more perfect than some other created being capable of judgment?