Final Exam Notes

These are notes for the final exam. They do not cover the biographical details of the philosophers we've covered. You do need to know these details: I suggest reading the introduction to each philosopher in the book for this information.

For this test, you should focus most on Augustine.

Augustine

Knowledge

• According to Augustine, there are two kinds of knowledge:
1. Knowledge of contingent truths based on perception
2. Knowledge of necessary truths based on reason
• Contingent truths are those that could possibly be false (my hair is red; I live in Tucson; there are eight planets in our solar system; all of these things could have turned out differently). Necessary truths are those that could not possibly be false (2 + 2 = 4; all bachelors are unmarried; triangles have three sides; none of these things could have turned out differently).
• The two types of knowledge work together: using perception, I might see an object with three sides; then using reason, I could conclude that since anything with three sides is a triangle, I am looking at a triangle.

Illumination

• How does knowledge by reason work?
• Augustine's answer is that it works by God illuminating our minds—when we learn a necessary truth, that is God—somehow—bringing our minds directly into contact with that truth
• Augustine has three arguments that illumination is how we learn necessary truths; we'll go through them
• The argument from universality and necessity:
1. We know some universal and necessary truths.
2. To know a universal and necessary truth is to be in contact with the Forms (remember the Forms from Plato?).
3. We cannot come into contact with the forms by perception!
4. God himself just is all of the forms.
5. Coming into contact with the forms is coming into contact with God.
6. When we know a universal truth, that is being in direct contact with God.
7. Coming into contact with God in this way is being illuminated by God.
8. Therefore, we are illuminated by God.
• The argument from language:
1. We can tell the difference in meaning between some co-extensive words (co-extensive words are words that refer to all the same things even though they have different meanings—like “triangle” and “trilateral”)
2. Since all we learn by perception is what the words refer to, we cannot learn this difference in meaning by perception
3. Knowing the meaning is understanding the form—we already saw that understanding a form is to be illuminated.
4. So we must be illuminated by God to tell this difference in meaning.
• The argument from hierarchy:
• This argument is confusing and weird: just know this: Augustine, like Plato, thinks there is a hierarchy of being and that the things higher up in the hierarchy have more being (or reality) than the things lower down.
• Because of these arguments, Augustine concludes that our knowledge of necessary truths is the result of illumination by God.
• Two important things to note:
1. Not everyone is illuminated equally: we all know it takes a lot of work to get good in mathematics.
2. Knowledge by illumination is NOT innate knowledge
• Maloney's two objections to illumination:
1. Augustine never told us what the process is by which illumination takes place
2. Some evil people know necessary truths, but surely a good God wouldn't illuminate evil people (if illumination is right, God sometimes illuminates evil people)

Creation Ex Nihilo

• Creation ex nihilo is creating something from nothing (“ex nihilo” means “from nothing”)
• Augustine thinks that we know about creations ex nihilo by reason: we know it by thinking about what it takes for change to be possible; Augustine's creation ex nihilo is not based on faith alone.
• Augustine thinks God is constantly creating the world from nothing—this is how change is explained, since change requires something to come from nothing
• Since God is constantly creating the world ex nihilo, two problems arise for Augustine—Why is there evil in the world? and How can we have free will?

The problem of evil

• It looks like the existence of evil is inconsistent with the existence of God. In fact, it looks like we can prove that God does not exist:
1. God is all-knowing, all-powerful, and all-good.
2. If God existed, he would know about any evil (all-knowing).
3. If God existed, he would be able to prevent any evil (all-powerful).
4. If God existed, he would want to prevent any evil (all-good).
5. So, if God existed, there wouldn't be any evil.
6. But there is evil—lot's of it!
7. So God doesn't exist.
• Augustine, of course, thinks God does exist, so he has to explain what's wrong with this argument.
• His response is to deny that there is any evil in the world. He says everything that we think is evil is really just an illusion of evil.
• What we think of as existing evil is really just a certain lack of good. Augustine will admit that some things are less good than others, but he doesn't think that proves that there is anything evil.

A problem for free will

• It looks like God's knowledge of the future is inconsistent with our free will. In fact, it looks like we can prove that we don't have free will if God knows everything:
1. If God knows that I will do action X, then necessarily, I will do action X.
2. For every action X that I will do, God knows that I will do it (since he knows everything).
3. For every action X that I will do, I will necessarily do it.
4. Actions that I must necessarily do are not free actions.
5. Therefore, none of my actions are free (and the same goes for everyone else).
• Augustine, of course, thinks that we do have free will, so he has to explain what's wrong with the argument.
• His response is to deny that necessary actions cannot be free.
• He says that free actions are just voluntary actions, and voluntary actions are just actions that satisfy our desires—if I find myself desiring a beer, and I then get up and grab a beer, that was a voluntary (free) action.
• Even if an action is necessary (or predetermined, or Fate, or whatever), it might still be one that satisfies a desire of mine. So necessary actions can be free actions!
• A problem for Augustine: it looks like his definition of a free action isn't strong enough. Consider some addicted to heroin: every time he shoots up, he is satisfying his desire, but surely he's not free—he's addicted!
• That's what you need to know about Augustine.

Boethius

The argument that we don't have free will

• Boethius believes in God and believes we have free will, so he's also interested (like Augustine) in figuring out what is wrong with the argument that says that because God knows the future, we cannot have free will
• Let's look at that argument again:
1. If God knows that I will do action X, then necessarily, I will do action X.
2. For every action X that I will do, God knows that I will do it (since he knows everything).
3. For every action X that I will do, I will necessarily do it.
4. Actions that I must necessarily do are not free actions.
5. Therefore, none of my actions are free (and the same goes for everyone else).

Rejecting the argument

• Remember that Augustine rejects the fourth step. But Boethius has a better idea: reject the first step
• Just because someone knows something, it doesn't mean that what they know is true of necessity!
• For example, I know that it's sunny today; but it could have rained—it's not necessary that today is sunny!
• This is about knowledge of the present—if we know something about the present, it doesn't follow that the present is that way of necessity. It's the same with the future.
• So Boethius says we have to fix the first step in the argument. He thinks the following is true:
1. If God knows that I will do action X, then I will do action X.
• See how that's different from the original first step? And look—you can't use the new first step to argue that we have no free will:
1. If God knows that I will do action X, then I will do action X.
2. For every action X that I will do, God knows that I will do it (since he knows everything).
3. For every action X that I will do, I will do it.
4. Actions that I must necessarily do are not free actions.
5. NOW WHAT?! We have not, and cannot, show that my actions are necessary, so we cannot prove that they are not free
• Boethius's point: if we fix the first step, then the supposed “proof” vanishes.
• Boethius concludes, like Augustine but for a different reason, that God's knowledge of the future does not threaten our free will. And Boethius is right (though there are other reasons to be worried about free will that we haven't talked about).

Anselm & Gaunilo

Anselm's Ontological Argument

• Anselm wants an irrefutable proof that God exists so that he can convince atheists of their error. His proof is called the Ontological Argument
• Here's the argument:
1. By definition, God is the greatest conceivable being (that's just what the word “God” means)
2. Assume, just for the sake of argument, that God does not exist.
3. Then we can conceive of (imagine) a being, call it X, just like God, except that X exists.
4. To exist is greater than not to exist.
5. So X is greater than God!
6. But (5) contradicts (1)—God is by definition the greatest conceivable being; so our assumption (2) must be false.
7. Therefore, God exists.

Reductio Ad Absurdum (reduction to absurdity)

• Anselm's argument is an example of a reductio ad absurdum, a type of argument commonly found in mathematics
• If you want to prove that something, call it P, is true by a reductio ad absurdum, you first assume the opposite (not-P) and show that this implies a contradiction; this allows you to know that not-P must be false and so P must be true

Gaunilo's Response

• Like Anselm, Gaunilo believes in God
• But Gaunilo does not think that Anselm's argument works. He says that using Anselm's argument, he can “prove” something that's obviously false—namely, that the perfect island exists.
• Here's the argument:
1. By definition, Kitekali (that’s a word I just made up) is the greatest conceivable island (that's just what the word “Kitekali” means)
2. Assume, just for the sake of argument, that Kitekali does not exist.
3. Then we can conceive of (imagine) an island, call it X, just like Kitekali, except that X exists.
4. To exist is greater than not to exist.
5. So X is greater than Kitekali!
6. But (5) contradicts (1)—Kitekali is by definition the greatest conceivable island; so our assumption (2) must be false.
7. Therefore, Kitekali exists.
• If an argument can be used to generate a false conclusion, then it is not a good argument. So there must be something deeply mistaken in Anselm’s argument. He has not, therefore, proved that God exists (to be fair, some people don't think Gaunilo's objection is any good; they think Anselm's argument is a good argument and that the perfect island argument is somehow different).

Descartes

Certainty

• Descartes wants to base science (which for him is identical with knowledge—science is everything we know) on a foundation of certainty. This is the view called foundationalism

  Foundationalism: Everything we know must be based on a few special beliefs that are known with certainty (those few special beliefs are the foundations of all knowledge).

• Descartes supposes he has lots of beliefs that are less than perfectly certain, so he wants to get rid of those before he starts doing science (can you see why?). How will he do this?
• He decides that there is a test for whether a belief is certain: if we can find any reason to doubt it, however slight, it is not certain; if we can find no reason, then it is certain.

• Descartes will use what he calls Method of Doubt to get rid of all his beliefs that are not certain.

  Method of Doubt: (1) For each of your beliefs, try to find a reason to doubt it. (2) If you can find a reason to doubt it, stop believing it. (3) Repeat until the only beliefs that you cannot doubt are left. You will be left with only beliefs that you know with certainty.

Talking with the Skeptic

• Descartes has a “conversation” with an imaginary skeptic to carry out the method of doubt (a skeptic is someone who thinks humans cannot ever know anything; Descartes is not himself a skeptic, though he does want to take the imaginary skeptic seriously and show him why he would be wrong.)
• Descartes and the skeptic agree that certainty requires very strong evidence: the evidence for a belief must be so strong that it is impossible for the evidence to be present but the belief to be false (consider an ordinary piece of evidence: a bloody dagger is evidence that someone is murdered. But when there is a bloody dagger, although it is likely that someone was murdered, it is possible that no one was. Descartes and the skeptic would agree that a bloody dagger is not good enough evidence to believe with certainty that there was a murder.)
• The skeptic says that none of our evidence is good enough for certainty. He divides our evidence into three kinds (1) evidence from perception in bad conditions; (2) evidence from perception in the best conditions; (3) evidence from reason. He finds a reason to doubt each of these kinds of evidence
1. Doubting evidence from perception in bad conditions: this is easy. Think of all the times you've gotten it wrong when believing something based on perceptions in bad conditions (you though you saw a deer through the fog, but it was a tree; you thought that was your friend in the distance, but it was a stranger; etc.). This means that there is reason to doubt anything based on perception in bad conditions, so it is not good enough evidence.
2. Doubting evidence from perception in good condition: this is easy. You believe that you're reading these notes right now. But you could be dreaming—think of all the times that you were dreaming but you thought you were awake! this means that there is a reason to doubt anything based on perception, even in the best conditions (perfect lighting, up close, etcc), so it's not good enough evidence.
3. Doubting evidence from reason: this is a bit harder. Surely it's possible, even if unlikely, that there is an evil demon controlling your brain and making all of your beliefs false—even your belief that 2 + 2 = 4 (and others based on “pure reason”. If it's possible, then there's a reason to doubt anything based on reason, so reason is not good enough evidence.
• The skeptic has apparently given Descartes reasons to doubt all of his old beliefs, so Descarte's method of doubt seems to have left him without any beliefs at all. The skeptic thinks he has proved that no knowledge is possible. Descartes is worried (how will he do science without a foundation of certain beliefs?)
• IMPORTANT NOTE: Neither Descartes nor the skeptic think we are actually being deceived by an evil demon! They both just admit that it is possible that there is such a demon, and so we cannot be certain that there is. Just because someone thinks something is possible doesn't mean they think it is so—I think it's possible for all of you to get A’s on this exam, but I don't think you will!

The light at the end of the tunnel

• In a moment of despair, Descartes says, “Fine! I give up! If there is a demon out there, then let him deceive me!”
• He then realizes something important: if a demon is deceiving him, then he himself (Descartes) must exist! He thinks, “I can't be wrong about whether I exist, because in order for me to be wrong about that, I would have to exist!”
• This is Descartes's famous Cogito argument
• Descartes says “Cogito ergo sum,” which means “I think, therefore I exist”
• So now Descartes knows with certainty that he exists; what's more he thinks that no demon could deceive him about what he (Descartes) is currently thinking about—Descartes can be certain about his own thoughts and ideas.
• Using just his knowledge of what his own thoughts are about, Descartes launches an Ontological Argument that God exists, much like Anselm's argument (“I know that my idea of God is an idea of the greatest conceivable being; suppose that there is nothing in reality that matches my idea; then I could imagine a being just like God but that exists; etc.”)
• So now Descartes knows with certainty that he himself exists, he knows for certain what he is thinking about, and he knows for certain that God exists.
• Since God is all good, he would deceive Descartes about things that seem absolutely obvious and true to Descartes(God wouldn't allow an evil demon to screw with Descartes, for example)—so now Descartes can get all of his beliefs based on reason back! It’s certain that 2 + 2 = 4!
• God also would deceive Descartes about things that he can see right in front of his face&mdashso now Descartes can get back all of his beliefs based on perception in the best circumstances!

Now we have a foundation

• So there's a happy ending to our story: Descartes found a foundation of certainty upon which he could build science. We just have to be careful and responsible in forming beliefs and we can rest assured that God won't let us go astray.