"Philosophy of religion" means "the study of the meaning and justification of fundamental religious claims, particularly about the nature and existence of God." Philosophy of religion is classically regarded as part of metaphysics, since according to most conceptions of God, if God exists heís in an important category of being different from the rest of the universe. Right? God isnít a body and he isnít any ordinary sort mind. Moreover, remember that metaphysics concerns basic beliefs which underlie many other philosophical beliefs -- and well, religious claims, as we all know, often underlie views about what we can know, how we can get knowledge, and how we should live. So all that is why philosophy of religion has been, traditionally, regarded as a branch of metaphysics. But more recently the philosophy of religion has been instead regarded as a subject unto itself.
Before we get into the subject itself I want to make something clear. I am not trying to attack your religious beliefs; I think you do have a right to believe, and not to believe, whatever you want. As I conceive of it, the purpose of the philosophical study of the philosophy of religion is not either to support or to undermine religion, but rather to examine the meaning and justification of belief in God to the best of our ability. Now some people are very threatened by any sort of clarification of their religious views, whether about the meaning of those views, or about whether those views can be supported by good reasons. If you are such a person, I implore you to change your attitude, if for no other reason than that some extremely religious people study the very questions weíre going to ask. For example, all the questions weíre going to ask are studied in depth at prominent Catholic universities, where sections about the philosophy of religion are included in introductory philosophy courses, which courses are taught by priests and other firm believers.
So to the subject itself. There are a lot of philosophical questions that can be asked about religious beliefs. But my view is that there are just two really important questions in this field. They are: (1) What is God, i.e., what is the meaning of the word, "God"? (2) Do we have any good reason to think that God exists, or to think that God does not exist? Still, there are other questions studied in the philosophy of religion. For example: What, if anything, would be good reason to believe that a miracle has occurred? Or: Is it possible for belief in Godís existence to be rational even though one merely has faith that God exists? Or: What might it mean for God to be "Father, Son, and Holy Ghost" as in Christian theology? But I think the two questions I listed are most fundamental. In saying they are most fundamental, I mean that the other questions in the field either contribute to answering one or the other or both of these questions, or else they are relatively unimportant. I mean, surely the most important questions we have to ask about religion are what God is, and whether we have any reason to believe God does or does not exist.
So letís examine the two questions in a bit more depth. To begin with the first: What is God, i.e., what is the meaning of the word, "God"? Now, what would count as an answer to this question? A definition, no doubt; maybe other sorts of answers would be acceptable, but what we would naturally expect is a definition. Now remember something from our discussion of definitions. Before we give a definition of a term we want to know what sense of the term we want to define. I might ask, "What is the definition of Ďbankí?" but until I said that I meant financial institutions rather than edges of rivers youíd be confused about what concept it was that I wanted defined.
Now, arenít there different senses of the word "God"? Surely there are. The word is used in different ways by different people. So before we try to answer the question, "What is God?" by giving a definition, first we have to get clear on which conception of "God" we are trying to define! Some people believe that there is more than one God. They are called polytheists. For example, the ancient Greeks were polytheists, officially anyway, polytheists. We arenít going to concern ourselves with the merits of polytheism. Some people believe there is only one God. That belief is called monotheism. But there is a huge number of different kinds of monotheism. Some people have the rather strange view that there is one God but God is simply everything that exists; in other words the whole universe is God. This view is called pantheism. Some people believe that only one God exists, but that God is like a watchmaker who wound up the universe and now does not intervene at all, not even to answer prayers: they are called deists. The old French Enlightenment philosophes, like Voltaire, were deists. OK, so where do ordinary Christians fit into this? They are theists proper. Theism is the view that exactly one God exists, which is an eternally existent spirit, which exists apart from space and time, and which is the creator of the world, and is therefore all-powerful; and usually this being is also thought to be all-knowing and all-loving.
So let us suppose that we decide we are interested in finding out what the word "God" might refer to, in the sense in which it is used by theists. In other words, we decide we are not interested in any polytheistic sorts of gods, or a pantheistic sort of god, or a deistic sort of god. What we want to get some grasp on is what the God of Abraham and Jesus is. And suppose we decide on the definition of "God" that informs the stated definition of theism. So we say that "God" means "an eternally existent spirit which exists apart from space and time, which is the creator of the world, and is therefore all-powerful, and which is also all-knowing and all-loving." But then there are a lot of questions to be answered about this definition. For example, what does it mean for a spirit to create anything? What does "all-powerful" mean? There is no shortage of questions that philosophers -- both believers and nonbelievers, mind you -- have about the very idea, the very concept, of the God in whose existence theists believe. We will discuss such questions in a little bit.
But first let me introduce the second question that I said was so fundamental in the philosophy of religion: Do we have any good reason to think that God exists, or to think that God does not exist? Now, what would count as an answer to this question? Well, of course, the words "Yes, we do" or "No, we donít"; but then these words should be followed by supporting arguments, and the conclusions of the arguments would be either "God exists" or "God does not exist." We will discuss several arguments that God exists, and one major argument that God does not exist.
Iíve already introduced the names of different kinds of belief that God exists. We can give a general description of someone who does not believe that God exists -- we can say they are nonbelievers. Nonbelievers come in two varieties. Those who believe that God does not exist are atheists, and their view is called atheism, whereas those who believe neither that God exists nor that God does not exist are called agnostics, and their position is agnosticism. Some people who donít think very much about the philosophy of religion tend to think that all nonbelievers are atheists, thus entirely ignoring a very importantly different position that some people take on the question of whether or not God exists, namely agnosticism. In its original sense, agnosticism is the view that we, humans, cannot know whether or not God exists. But there are some other views, which are not as extreme as that, which I am lumping in with agnosticism in that original sense. For example, if I say that I personally do not know, at present, whether or not God exists, then I am an "agnostic" in a looser sense of that word. I would even lump in with the agnostics those people who simply have no views about God, havenít thought very much about it, and donít care. I doubt there are very many such people these days, but those people too may be called "agnostics" in a loose sense of that term.
In the second part of our examination of the philosophy of religion, we are going to be considering the merits of theism, insofar we are going to evaluate some arguments for the existence of God, and of atheism, insofar as we are going to examine one important argument against the existence of God. But we are not going to be considering the merits of agnosticism. This is simply due to time constraints. But I can at least tell you what it would mean to consider the merits of agnosticism. Agnostics claim that the existence of God cannot be known; so to examine the merits of agnosticism would involve examining whether that claim have any good arguments in its favor. It might also involve examining whether one can be, in some sense, justified in not thinking about whether or not God exists. In other words, might we be justified in simply ignoring the issue of whether or not God exists? No doubt some theists would want to take some agnostics to task for not even thinking about whether or not God exists. And Iím sure you can imagine a debate, then, between them, where the theists on one side are saying that the agnostics really ought for the sake of their souls to be thinking about whether or not God really does exist, and the agnostics on the other side are saying that they are perfectly well justified in holding that thinking about it is a total waste of time. Well anyway, we are not going to listen in on that debate, however interesting it might be, because we have bigger philosophical fish to fry. And the first item on our menu, as I said, is the question of what God is.