When university students sign up for philosophy courses, they suffer under the reasonable delusion that they're going to study questions pertaining to the meaning of life. Substance-induced thoughts aside, these are the kinds of questions people ask when faced with pivotal moments in their own lives. Who am I? How should I live?
Since we're naturally drawn to these questions—and since these questions are philosophical—why wouldn't a philosophy course deal with these questions?
But that's not the way it works it all.
Here's an all-too-familiar scenario. It's the first day of John's philosophy course. Before him is his open spiral notebook. His pen is poised over the page. "This course is called Introduction to Metaphysics," the professor says. "Metaphysics is the study of the underlying nature of reality. In the following lesson, we will begin to talk about what it means for anything to even be real at all."
John jots frantically. Metaphysics. Underlying nature of philosophy. What is real? Double-underline under the word "real."
The next lesson comes. John arrives early, sits, opens his notebook. He's eager for instruction. Then the professor begins to talk about a paper by W.V. Quine called "On What There Is." John had read this paper the night before and didn't understand it. The first line reads, "A curious thing about the ontological problem is its simplicity." What does that mean? John asked himself. He hopes the professor will help him understand.
But the professor's lecture isn't a help at all. John can barely wrap his head around what is being talked about. To the extent that John does understand what the professor is talking about, he can't understand why the professor is talking about what she's talking about. John drops the course.
Philosophy as a field of study divides inelegantly into two traditions: analytic and Continental. Analytic philosophy studies philosophy as continuous with the sciences. But unlike the formal sciences, there are no well-defined research programs or methods to solve problems in the field. The only thing tool available is logic and argumentation. To the extent that they can, so-called analytic philosophers try to state their arguments as clearly and logically as possible, and then it's the business of others to determine how sound those arguments are.
The other tradition of philosophy—Continental philosophy—studies the philosophical works of major figures of Continental Europe. This tradition tends to treat philosophy more as an art than as a science. It doesn't exactly eschew logic and argumentation (though some figures in this tradition would, in fact), rather it thinks that there's more to doing philosophy than trying to formulating philosophical issues like scientific problems.
There are several shortcomings to this approach from Continental philosophy, but we'll leave them aside for now, because the classroom setting described above is in the tradition of analytic philosophy, which is what we'll be looking at here.
W.V.(O.) Quine is a major figure in analytic philosophy and is famous for a number of arguments pertaining to logic, language, and metaphysics. His paper "On What There Is" tries to get clear about what's at stake when there's a dispute about what is real or what exists.
This matters because there a number of puzzling features of natural language where it seems like we can form true statements about entities that don't exist. (You may so that this already sounds like the beginning of a very abstract dispute. To which I reply, "Of course. We're talking about philosophy.") Let me give you an example.
Here's a set of statements I take to be true about Sherlock Holmes:
(1) He lives on Baker Street.
(2) He's got a partner surnamed Watson.
(3) He's a detective.
(4) He's a drug addict.
(5) He plays the violin.
All these sentences I take to be true and yet Sherlock Holmes doesn't exist. How can we refer to a person or make sentences about him if he doesn't exist?
Plato was the first one to recognize this problem. It is, incidentally, a peculiarity of virtually every known language.
You can even, if you want, simplify the problem.
Child 1: There is no such thing as Santa Claus.
Child 2: Uh-huh.
Child 1: Nuh-uh.
Child 2: How are we talking about him, then?
Child 1: ...
This kind of puzzle is what Quine takes up in his essay "On What There Is."
As a good logician, he wants to abstract from natural language and say that when we really want to take seriously whether somebody or something exists, we have to capture it in a formal language, symbolic logic.
Take the sentence, "Sherlock Holmes is a detective."
If you translate this sentence into predicate logic, it might look something like:
A(x)[S(x) --> D(x)]
Which reads: "For all x, if x is Sherlock Holmes, then x is a detective."
Why is Quine bothering with stuff like this? He thinks that a formal language like predicate logic is about the best tool we have for philosophy. He also tacitly accepts that ideally all scientific statements could be translated into such a formal language and as a result we could see all the logical inferences.
What we have done with the natural-language sentence about Sherlock Holmes is captured the sentence as a hypothetical. This is to say that if there is such a thing as Sherlock Holmes, he must be a detective.
But in this next bit of reasoning, I think Quine clearly goes wrong. Interestingly, he thinks that this hypothetical claim ("If x is this, then x is that") is tantamount to claiming that x exists. Most modern logicians would not agree with Quine on this point at all.
Again, we're not saying that somebody named Sherlock Holmes exists, but were he to exist, he'd be a detective. If the hypothetical statement really is the hidden structure of the sentence, then when we are making claims about a fictional person, we're not committing ourselves to there being real fictional persons, whatever that means. However, as soon as we claim, "There is such a thing as Sherlock Holmes," then we're obviously talking about Sherlock Holmes existing, and we can say that's false. That's how most modern logicians would interpret the statement.
Quine doesn't like this line, but it's for completely arbitrary reasons. He writes in the paper that once you have a "bound variable," you're committing to that variable being real. A bound variable, for example, would be when you say in logic "For all x..." or "There exists some x..." As I said, contemporary logicians would say, as looks to be the case commonsensically, when you're saying "There exists some x..." you're committed to the thing existing but when you make a hypothetical statement "For all x..." or "If x..." you're not committed to existence. This just comes with the nature of translating the formal language.
Whatever you may think of Quine's solution or the logician's patch, Quine and the logicians would say that these stipulations are really only about translating natural logic into a formal language. They don't tell you anything deep about reality. They don't tell you how to determine what does or doesn't exist. If you wanted to ask about any other thing—take your favorite: aliens, Sasquatch, the Loch Ness Monster—Quine and the logicians don't think you can just determine it in your noggin. You have to check the world and look for empirical evidence, as you would with any other science.
So what value does the discussion have? Well, at the very least, it can help us get clear about our ideas and try to help us demystify some of the puzzles that get created by ordinary language. That's something.