TOPIC: Lecture 4.2 Aquinas Phil Religion Aquinas Cosmological Arguments for the existence of God. Critiques of Aquinas arguments. KEY TERMS/ GOALS: Cosmological argument. The problem of Infinite Regress. Be able to summarize one of Aquinas argument in a paragraph. Empirical evidence. A priori evidence. READING: St. Aquinas, The Existence of God. (In Perry, p. 44-46) Focus on Aquinas first and second argument, 44-45. CONTENT: Last time we saw that Pojman critiqued arguments that try to show that God exists based on personal experience. He argued that those arguments fail because they do not give good justification for proving that God exists, since people s experiences vary too much, and since religious experience cannot be confirmed. What we should take out of that lecture is that if we are going to prove that God exists, we should find better arguments that do not rely on people s personal experiences. Aquinas does just that. Aquinas argument is very common: You may have heard arguments like, God must have caused the universe because it could not have been created by chance alone, or The existence of living creatures on Earth must have been caused by God because they could not have just sprung from nothing (or from inorganic materials). Aquinas argument aims to prove that God must exist in order to create the things around us. Incidently, his argument is similar (but not the same!) as Paley s Argument from Design. Paley argues that LIVING CREATURES are DESIGNED in such a complex fashion, that some Intelligent Designer must have designed them. Aquinas on the other hand, says that the UNIVERSE MUST HAVE BEEN CAUSED to come into existence. He focuses on what the ORIGINAL CAUSE must be for ANYTHING to exist. Aquinas uses a kind of argument called COSMOLOGICAL ARGUMENT, where cosmological refers to causation. Cosmological Arguments use a general pattern of argumentation that makes an inference from certain alleged facts about the world (cosmos), argues that something must have caused those things, and then concludes with the existence of a unique being, generally identified with or referred to as God. Among these initial (empirical) facts are that the world came into being, that the world is contingent in that it could have been other than it is, or that certain beings or events in the world are causally dependent or contingent. From these facts philosophers infer either deductively or inductively that a first cause, a necessary being, an unmoved mover, or a personal being (God) exists. So, Cosmological arguments take empirical observations that things change or exist, and then infer that something must exist to cause those changes or things to exist. Aquinas gives five ways to prove that God exists (44). We will focus on the first two.
AQUINAS FIRST ARGUMENT In the first argument, he notes that surely, as our senses show, some things in the world do change (44). No one will deny that summer changes into winter, hot water change to cold water, wax might change to liquid if it s heated and then back to a solid when it cools, etc. We can think of these things as effects. Just as a broken window is the effect from a rock being thrown into it (which is the cause), so, too, summer and winter are the effects of temperature changes and position of the Earth to the sun. The evidence to support the fact that things exist and change is that our sense show that it is true. The evidence, then, is empirical. Empirical means that something is known via our senses, by seeing, hearing, touching, smelling, etc. Empirical evidence is evidence based on the fact that we saw, smelled, heard, or felt it. (See below for a more detailed definition). Our first premise is: P1. Things change (by empirical evidence.) In other words, there are effects. Next, Aquinas discusses the nature of change itself. Things have the property of actuality and potentiality. For example, hot water is actually hot right now, but it has the potential to be cold. He notes that 1) something can only undergo a change if it has the potential of changing into something else (i.e. hot water can undergo a change because it has the potential to be cold). And 2) a thing can only cause a change if it is actually something. That is, hot water can change only if it is actually hot. We can write this premise as: P2. Something can change from X to Y only if it has a property X in actuality, and the potential to become Y. Let s think about this premise for a minute. Hot water can only change from hot to cold if it is actually hot right now, and has the potential to be cold in the future. This makes perfect sense. We may critique it by finding an example where X CAN change to Y even though it does not have the potential to become Y. But this possible counterexample seems false. We wouldn t want to say that I could change into Superman, even if I don t have the potential to become Superman. Nor would we say that water has the potential to become fire even if it does not have the potential to become fire. So, I think we can safely say that premise 2 is reasonable. (There are other ways to critique the premise. You could come up with a counterexample where X changes to Y even if X is not actual, but that seems absurd as well). Aquinas next gives the principle of non- contradiction. He says while a single thing can simultaneously be in actuality with respect to one property and in potentiality with respect to another, it cannot simultaneously be in actuality and potentiality with respect to the one and the same property (44-45). In other words, if something can be actually COLD and have the potential to be HOT (hot and cold are two different properties), but something cannot be both hot and cold simultaneously. Nor can something that is actually hot be potentially hot as well (the thing would be hot, not potentially hot). We can summarize Premise 3 as: Premise 3: Something cannot be actually X and have the potential to be X at the same time. Now, Aquinas draws an inference from Premise 3. He says It is therefore impossible for a thing that undergoes a change to cause that change, or for something to change itself (45). Thus: Premise 4: Whatever undergoes change must be changed by another thing. (i.e. If X changes to Y then it must be changed by Y). In other words, effects must have causes.
This is tricky, but let s think this through. Let s take something that is undergoing a change, say hot water that has the potential to be cold. Hotness itself cannot cause coldness (because it is hot, not cold). So if something changes from hot to cold, we do not say that the coldness is CAUSED by the property of hotness. Something else caused it to be cold, namely the property of coldness. If we have hot water, then there must be some other property in the water (other than hotness) that changes the water to cold (namely coldness). Aquinas did not have the scientific knowledge that we have now to explain temperature in terms of mean kinetic energy of molecules, but the same idea applies. We can explain that hot water has rapidly moving molecules, and it has the potential of having slower moving molecules. But what causes the molecules to change speed is NOT the rapidly moving molecules itself. It is caused by other forces like entropy, the environment around it (whether the stove is on or off, the temperature of the air), etc. What s important about Premise 3 is to think about the property of existence itself. If something actually exists, then it may have the potential to not exist. But the thing that would cause something to not exist is NOT the property of existence itself, it has to be the property of non- existence. Think about something that exists (the table I am writing on). It exists now, and if it were to change, it would be non- existing. But what caused the change is NON- EXISTENCE. Now think about the table as non- existing. Can it change back to existence? Only if there was a property of EXISTENCE around to change something into existence. But now consider that nothing at all exists. That is EVERYTHING is non- existing. Is it at all possible for NON- EXISTENCE to change into existence? No, because nothing exists, not even the property of existence to change things into existence. So, whatever undergoes change must be changed by another thing. If X changes to Y, then Y must exist in order to change X. Now comes the fun part of his argument. He gives a potential problem, called the problem of the Infinite Regress. He says if this other thing undergoes change, it also must be changed by something else, and so on. (45). P5. If Y changes to Z then it must have been changed by Z. Now we have a potential problem. If something changes, some other thing would have to exist to cause it to change. But if something has to exist to cause Z to change, then you can see that the series of things that must exist in order to cause changes can go on and on. We would always need to appeal to something else to explain the effects. If a window is broken (an effect) we can ask what the cause is (the rock), but then we have to ask what the cause of the rock is (erosion of mountains), and what the cause of the erosion is (gravity) and what the cause of gravity is, and on and on ad infinitum. It is a problem, though, to have this series of causes and effects continue forever, because if there was no START to the series of events, then there can be no ENDING point. Thus, we must note that P6. There cannot be an infinite regress of causes. That is, if there is no FIRST CAUSE to start the chain of events, then there would be NO EFFECTS. But, as we agreed in the first premises, there ARE effects. We can see them everywhere. So there MUST be a first cause to start the chain of events. Aquinas example is that a stick can only something only if a hand moves the stick, where the moving stick is the effect, and the hand is the primary cause. C. There must be a FIRST CAUSE. Now, to define the FIRST CAUSE, we must add that it cannot have been caused or changed by anything. That is, there must be something that exists but did not depend on anything to cause it to exist (otherwise we d ask
where THAT think came from). The FIRST CAUSE also must be able to cause things to change, but it itself did not depend on any causes for it to exist (otherwise we d ask what caused THAT thing). It looks like the thing we are talking about has to be pretty powerful. It doesn t have to be caused, but it can start the whole chain of events of causes that lead to the effects that we see today. Aquinas notes (rather flippantly) that everyone understands [the First Cause] to be God (45). Thus we may add another premise, just to define First Cause as identical to God. *The First Cause is God. This is a definition statement. Do not add any other properties to God. Aquinas has said nothing about whether this God is all- powerful, all- knowing, or kind or anything. The only property we have given to God so far is that it has the ability to cause change but it does not itself rely on anything to change it. Here is the outline of Aquinas first argument: P1. Things change (by empirical evidence.) In other words, there are effects. P2. Something can change from X to Y only if it has a property X in actuality, and the potential to become Y. P3: Something cannot be actually X and have the potential to be X at the same time. P4: Whatever undergoes change must be changed by another thing. (i.e. If X changes to Y then it must be changed by Y). In other words, effects must have causes. P5. If Y changes to Z then it must have been changed by Z. P6. There cannot be an infinite regress of causes. C. There must be a FIRST CAUSE where First Cause is something that does not itself depend on anything to change it or cause its existence, and First Cause = God. Here is a shorter way (and a more common way) to outline the argument, that may help you understand it: P1. Change exist. P2. All change must have a cause that is not itself. P3. The series of changes/ causes can t go back to infinity. P4. If there is no first cause, there cannot be any effects/ change. P5. But, from Premise 1, we have observed that there are effects/ change. C: So there must be a FIRST CAUSE of change, which is not itself changed by anything. E.g. God This outline has the essential ingredients of a Cosmological Argument. It starts with the empirical observation that changes (effects) exist, and then intends to prove that something (God) must exist to cause those effects. Premise 2 has summarized why things must have a cause. Recall that Aquinas explained that some property that is actual (X) cannot change to Y something else (Y) has to change X from Y. Premise 2 relies on a form of reasoning called a priori reasoning (see below) which is contrasted to empirical evidence. Premise 3 and 4 summarize the Infinite Regress problem. Premise 4 gives us an inference (a conditional statement) that IF there
is no First Cause, then there would be no effects. But, since we do see effects (from Premise 1), then it cannot be the case that there is NO First Cause. So, the conclusion is that there MUST be a First Cause, which we call God. EMPIRICAL AND A PRIORI REASONING. Before we briefly explain Aquinas second argument (and then critique his arguments), let us take a little break and discuss the difference between empirical and a priori reasoning, since Aquinas makes use of both kinds. Empirical (also, a posteriori) and a priori. Empirical evidence is drawn from observation or other senses. Empirical premises are factual statements about the world. For example, suppose I argue that The cat is on the mat. If I justify the statement by saying that I SAW or observed the cat on the mat, then I am using empirical evidence. But not every statement is supported empirically. Suppose I say that 2+2=4. It s not like we go around checking whether that statement is true by observing numbers. We know that the statement is true by using pure reason. A priori evidence is justified by reason, not by empirical observation. The statement, 2+2=4 is justified by reason, not by empirical observation. Don t get confused: We are talking about what kind of evidence we are using to JUSTIFY the conclusion that 2+2=4. We are not talking about the origins of the knowledge, or how we know that 2+2=4. These are two different questions. You might suppose, that is, that the only way that we know that 2+2=4 is because we learned about math in school, observed that putting two stones plus two stones together gives you four stones, etc. It is true that we might have acquired the ability to do math by using some empirical observation. But the question is not how we know math, but rather, what justifies the statement that 2+2=4. We know that this statement is true because we reason about it, we don t have to check facts in the world to see that it is true. Empirical arguments (or a posteriori arguments) have at least one premise whose truth is supported by observation. Here is an example argument that uses empirical evidence: P1: Bees pollinate flowers. P2. This is a bee. C: This bee pollinates flowers. The truth of Premise 1 is justified by empirical observation. A priori arguments are derived by or designated by the process of reasoning without reference to particular facts or experience. A priori arguments have NO premises whose truth is supported by empirical evidence. For example, All bachelors are unmarried males is a definition. Suppose I say that Jim is a bachelor. Then, you know for certain that Jim is an unmarried male. You have concluded that Jim is an unmarried male, not by going out and checking the world (you didn t have to actually look at Jim and interview him to see if he was unmarried and a male). You just knew that if All bachelors are unmarried males, and Jim is a bachelor, then he must be an unmarried male. You can justify your conclusion by reason alone. The difference between empirical and a priori reasoning might be confusing at this point. However, it is very important, since it asks what kinds of evidence is being used to support an argument. Both kinds are viable kinds of evidence, and both offer good justification, although it is a good question to ask whether either kind offers better support for an argument. That is, you might think that empirical evidence is better because seeing is believing. If you saw a burglar in your house, you would be a fool not to act on that evidence. On the other hand, eye witness testimony is often faulty, memory of sensory experience is not often reliable, we could be
hallucinating or seeing illusions, we could be dreaming that we saw a burglar, etc. All these factors make it less likely that the empirical evidence is reliable. Using a priori reasoning might seem more reliable, because it deals with reasoning faculties. After all, if you know the definition of mortal (that is a creature that dies and does not live forever), and you know that Socrates is mortal, then you know that Socrates will die and not live forever. No further justification is needed to prove your conclusion. We will discuss empirical and a priori arguments more when in our section on Epistemology (the study of knowledge). It is interesting to note, though, that some statements can be justified by either empirical evidence or a priori evidence. Take All men are mortal. We can say that it is simply a definition that if you are a man, then you are mortal (and mortal just means that you will die). On the other hand, we know that all men are mortal by empirically observing that every man (indeed every living thing on Earth) dies. I find this to be a cool feature about some arguments: Sometimes you can argue by appealing to empirical evidence, and sometimes you can argue by a priori reasoning. I raise this issue now to point out that Aquinas uses both kinds of evidence in his first argument. Premise one is empirical. We know that things change because we see them change. But Premise 2 says basically that every effect has a cause. Now, Aquinas could have argued this with empirical evidence, because we can go out and test this empirically. That is, we can see that the water turns hot because the stove was on which caused it to change from cold to hot. But Aquinas didn t argue empirically. He argued by appealing to what we know about the definitions of potential and actual properties. He argued that if something is actually hot, then it something else must cause it to change properties. After all if something is hot, the hotness itself cannot change to coldness (otherwise it wouldn t be hot, it would be cold). Play around with his argument and explain it in various ways on the discussion board. What you will be doing (with premise 2 at least) is trying to figure out what is meant by potential and actual properties and what we know by causation. It is an exercise in using a priori reasoning. The rest of the premises also appeal to a priori reasoning, since he reasoned that there cannot be an infinite regress of causation (it must stop somewhere). Also, he reasoned that there must be a First Cause since we see that there are effects now, and there would be a contradiction if there was no first cause to start the process that lead to the effects that we observe. He concludes that there must be a First Cause/ God. Aquinas Second Argument. This argument is similar to the first, in that it appeals to an empirical fact (things exist) and concludes that God must exist in order to cause those things. He talks about existence, rather than change, and he appeals to efficient causation. An efficient cause is explained in various ways by philosophers who explain Aquinas argument. But I find that it is distracting and unnecessarily confusing to explain it in any other way than to equate it with causation. You can translate his phrase into causation and know that what Aquinas means by efficient causes come into series is simply that there are causes and effects. For example, a rock through a window causes the effect of the broken window. P1. Things cause effects. (empirical evidence) His second premise is that things cannot cause itself to exist. He says We do not, and cannot, find that something is its own efficient cause for if something were its own efficient cause, it would be prior to itself, which is impossible (45). That is, if X exists now at time 3, it cannot be the cause of its own existence, because in
order to cause itself to exist, it would have to exist previous to time 3, namely time 2. But if it existed at time 2, then it would also have to exist at time 1 in order to cause it to come into existence at time 2. We ve run into an impossibility: If something causes itself to exist, then it would have to exist in order for it to cause itself to exist. It simply can t be the case that it causes itself to exist. P2. Something cannot cause itself to exist. (it must have been caused by something else). Now we have an infinite regress problem again. If something exists, it must have been caused by something else. But then, THAT thing must have been caused by something else. Let me put this in ordinary language: I exist because I was conceived in the back of a Pinto in the 70 s by my hippy parents. But now we have to ask why they exist. They exist because of their parents. Their parents exist because of their parents. We have a regress of causes. But, importantly, this regress cannot go on and on. If it did, then there would be no beginning point for the first thing to start. That is, if my parents parents, etc. ad infinitum never existed, then neither would I. But I clearly do. So someone somewhere had to have caused the chain of events that lead to my existence now. Thus, P3. We cannot have an infinite regress. P4. If there is no first cause, there would be no later cause. Now we see a contradiction, that if there were no cause to start the whole chain of events, then we would not see the effects. But we do see the effects: That is, things exist around us. P5. But there obviously are later causes (they created the effects we see). (re- statement of P. 1) C. So there must be a First Cause, which we mean that it causes the series of effects, but it does not rely on being caused. We call the First Cause God. There are subtle differences between Aquinas first and second argument. Read the arguments (in your Perry book) carefully to understand the subtlety. The first one is about change, and the second one is about causation. For your Final Exam, I will ask for a definition of the infinite regress and I will have you explain either the first or second argument in one paragraph. CRITIQUE OF AQUINAS ARGUMENTS. Recall the six ways to critique an argument: 1. Check for validity (if it is a deductive structure). 2. Check for soundness (e.g. are the premises true?). 3. Check for strong or weak sample sizes (if it is an inductive argument). 4. Check for unstated assumptions in the argument. 5. Check for unwanted or absurd consequences of an argument (i.e. assume the argument is sound). 6. Check for informal fallacies.
Let s try some of these on Aquinas arguments. *Argument 2 has an inherent contradiction (it s unsound). Premise 2 points out that something cannot cause itself to exist. This means that if something exists, it has to be caused by something else. But then, Aquinas turns around and simply states that something CAN exist without itself needing to be caused, namely the First Cause/ God. But look, if God can spring into existence from nothing, then why can t the universe? Why couldn t it be the case the whole series of causes and effects simply started without itself needing to be caused? So, if God can be caused by nothing, then why can t it be the case the cause- effect series that we see is caused by nothing? *Both arguments rely on the assumption that something has ONE cause. That is, the effects of change from hot and cold has one cause. Sometimes this is true: broken windows are caused by thrown rocks. However, there are numerous things that are caused from more than one source. Summer does not just have one cause: A lot of factors like temperature, air pressure, position of the earth, etc. must be in place. So, we can accept that things must be caused, but why does they have to be caused by ONE cause. Why can t there be MULTIPLE FIRST CAUSES? That is, multiple Gods that create the universe? *Aquinas argues that there cannot be an infinite regress, but we might want to ask why it is IMPOSSIBLE to have the series of causes and effects go back to infinity. Why can t the universe be infinitely old? Now, Aquinas does argue why the cause/effect chain cannot go back to infinity. But notice that even if we accept that no event can happen without having a cause, it does not follow that there has to be a FIRST Cause. The Universe could have always existed, and things could have always changed. This would maintain the idea that effects have causes, but show that there does not need to be a First Cause to start it all. This is a way of accusing Aquinas of committing the informal fallacy of begging the question. Recall that Premise 2 says that All things have causes. Then his Conclusion is that There must be a first cause. His conclusion is in the premise, which is begging the question. He needs to argue why all things must have a cause. Why can t something come from nothing? For example, why can t there be a Big Bang which itself wasn t caused by anything? *Finally, suppose that we accept that there must be a cause to start the process of cause/effects. But now let s offer another explanation, namely that the Big Bang started the universe and the whole chain of causes and effects. Now we have accepted Aquinas argument, but we are questioning his use of the word God to equate with First Cause. I don t think Aquinas would be happy with saying that the Big Bang is the First Cause. Nor would he want to equate The Big Bang with God if each of these is interchangeable with First Cause. Although Aquinas explicitly argues that the First Cause is simply to be equated with God, I think he is throwing more assumptions about God s properties in the mix. After all he says everyone understands [the First Cause] to be God. What is he relying on, here? Do we really understand the First Cause to be God? Is there any evidence in the text that Aquinas is assuming the Christian all- PKG God to be the God in question here? ASSESSMENT: To prepare for the Philosophy of Religion exam, be able to explain Aquinas first or second argument in a paragraph. Be sure to memorize the argument outline, but also be able to explain each premise in your own words. Try out your paragraph in the Discussion Board. DISCUSSION QUESTIONS: Have you heard versions of Aquinas argument in daily life? Have you used a version of Aquinas argument? How appealing is his argument?
What are some critiques of Aquinas argument? Is the critique that I gave about the Big Bang devastating to Aquinas argument, or can you find a way to defend him? Final Note: I don t mean to confuse you, but I do want to point out that there are lots of ways to explain or outline an argument. I thought I d include these two ways, from Elliott Sober, from his textbook for introduction to Philosophy, called Core Questions in Philosophy (2009. fifth edition. Pearson education, New Jersey: 38-39). I thought these outlines might help you understand the two arguments better. Be sure to do your own outlines and share them on the Discussion Board (I know it s difficult, but try it out.): Aquinas First Argument: P1. In the natural world, there are objects that are in motion. P2. In the natural world, objects that are in motion are always caused to move by objects other than themselves. P3. In the natural world, causes must precede their effects. P4. In the natural world, there are no infinite cause/ effect chains. P5. Hencce there is an entity outside of the natural world (a supernatural being), which causes the motion of the first moving object that exists in the natural world. C. Hence God exists. Aquinas Second Argument: P1. The natural world included events that occur. P2. In the natural world, every event has a cause, and no event causes itself. P3. In the natural world, causes must precede their effects. P4. In the natural world, there are no infinite cause/effect chains. P5. Hence there is an entity outside of nature ( a supernatural being), which causes the first event that occurs in the natural world. C. Hence, God exists. When you read Aquinas, try formulating an alternative outline of the arguments in your own words. Doing this will greatly improve your understanding of the argument. Don t be afraid to put the text down, step back and close your eyes, and think about the argument. When you write a summary, use your own words and experiences. Doing this will internalize your understanding of the argument.