Every activity worth doing must serve some purpose. A purpose writ not in the fabric of the universe but in the desires of particular individuals, such that the activity is worth doing for them. The reasoning behind this assertion is simple to explain: if we suppose there are purposes independent of human desires that don’t serve them in some way then it is clear that, objectively speaking, we would be better off ignoring them. (If there were two groups of people, one that ignored such purposes and one that paid attention to them, the first would have an advantage over the second.) Clearly then such purposes are an absurd idea, probably invented, if I may digress, to manipulate people into ignoring what was best for themselves. Of course this account of human activity doesn’t really rule out much; it is broad enough to account for activities that are done because of the belief that they worth doing alone, that is essentially what a fad is. But any activity that persists, I maintain, must serve a certain persistent class of interests. And as philosophy is an activity that persists we can thus ask what the purpose of philosophy is, and what interests it serves, and expect an answer more substantial than “people like doing philosophy”.
Of course that is a highly theoretical question and it may seem a pointless one to ask. After all philosophy does get done, and people continue to be paid for it; for many philosophers that may be enough. And as I have just pointed out philosophy probably serves some purpose, so what is the point in losing sleep over what that purpose is exactly? Well it should be obvious that an activity can be done better or worse. And to determine how well an activity is being done it is necessary to examine how well it is accomplishing its purpose. So if you don’t know what the purpose of what you are doing is then you are essentially lost in the dark, stumbling first in one direction and then another, but never knowing whether you are actually getting somewhere. Similarly, knowing the purpose of an activity can allow us to determine principles about how it should be done. For example, consider a band of proto-astronomers. These proto-astronomers have begun to make discoveries that question certain established religious principles, which some of them may think is a bad thing. This may lead them to question what the purpose of proto-astronomy is. Is it to tell people a comforting story about the heavens? Is it to make accurate measurements about the time of year? Or is it to discover facts about the heavens? Obviously the proto-astronomers are free to pick any of these as the purpose of their discipline, but they can only really pick one because of the possibility of developments that lead to a conflict between them. And which one they pick will determine how they go about their proto-astronomy, because more powerful telescopes are really only necessary if you are interested in astronomical truths. Similarly, the same can be said about philosophy: knowing what the purpose of philosophy is will better allow us to separate good philosophy from bad and it will inform us about how to do philosophy.
One might be inclined at this point to try to discover the purpose of philosophy by looking at how philosophy is actually used. But, unfortunately, most modern philosophy stays confined to the academic world, and thus appears quite useless. This does not imply that philosophy is useless, but rather that the purpose of philosophy is unclear. Our proto-astronomers were in a similar position: they couldn’t extract the purpose of proto-astronomy from what they had already done, rather they were required to give proto-astronomy a single purpose. So, if we have to give philosophy a purpose rather than simply discover one (because, like proto-astronomy, philosophy may already serve some purposes, but things are in such a confused state that extracting one is impossible), then we might start by looking at the purpose of other disciplines to see whether philosophy fits into some established mold.
We can divide human activities by their purpose into three major groups: the practical, the scientific, and the artistic. The practical activities revolve around being able to get something done, such as fix a car or program a computer. Obviously then philosophy is not a practical activity, because nothing gets done through philosophy except philosophy itself. The scientific activities revolve around discovering truths about some subject matter, truths that it is possible to use to better accomplish our goals relating to that subject matter (by giving us the ability to make better predictions or tools). Now obviously philosophy does contain various truths. At the very least “there are some true philosophical claims” is a true philosophical claim, since its negation is a contradiction. And it seems likely that there are other philosophical truths as well relating to what the mind physically is, and so on (or at least they certainly don’t seem like matters of opinion). But, while philosophy does contain such truths, it is implausible to maintain that discovering them is the purpose of philosophy. These truths are almost universally practically worthless; knowing them does not give us any more control over our environment, nor do they help us produce useful tools. Indeed people seem to be able to get along quite well without knowing philosophical truths, since it seems likely that most people don’t know them, nor would knowing them help them out. When philosophers disagree about philosophical truths it is not the case that one of them can be put at a practical disadvantage by their error, as they would be if they were wrong about a scientific truth.
This might seem to imply that the purpose of philosophy must have to do with the third kind of activities identified, the artistic kind. The artistic activities revolve around producing things that immediately give pleasure to people or which entertain them. And it might be argued by some that philosophy is purely a kind of intellectual entertainment. I would disagree, however. I admit that philosophy might entertain or be enjoyable, but the same thing can be said about any written material, such as a book about science aimed at the general populace. But to conclude on the basis of this that the purpose of science is to entertain is to confuse the presentation with the content. And the content of philosophy is incompatible with the idea that philosophy is a kind of art, because the content of philosophy revolves around proposals, objections, and counter-proposals. One cannot, however, object to a piece of art, one can only criticize it or try to make a better piece of art. Similarly, the measure of great philosophy under this view would be its public reception, which would make Ayn Rand a better philosopher than Kant. And that’s a reductio ad absurdum if I have ever seen one. Of course I wouldn’t deny that we couldn’t simply decide that the purpose of philosophy is to be a kind of intellectual art form and proceed to do philosophy on that basis, but the activity that would result would be so alien that it wouldn’t resemble what had previously been called philosophy.
Now just because philosophy doesn’t fit neatly into one of those three categories doesn’t mean that it has no purpose; the categories are not exhaustive. Mathematics, for example, doesn’t fit into them because, properly speaking, mathematics doesn’t contain truths. Admittedly it is natural to speak of mathematical truths, and such language rarely causes confusion, but properly speaking there can only be truths where our statements aim to reflect some external subject matter. But the subject of mathematics is not external to it; rather it is created by it. As Hilbert pointed out there is nothing more to the number one than the properties we define it as having; that is why deduction is the basis of mathematic reasoning rather than induction, the basis of scientific reasoning. The point of mathematics is not its truths then, rather it serves as an instrument to describe scientific truths. And in this way it serves a purpose, indirectly, because correctly capturing scientific truths serves a purpose. But philosophy is not mathematics, a fact easily demonstrated by pointing out that there is more to the subject matter of philosophy, i.e. things such as knowledge and ignorance, than how we formally define them.
What then is left for philosophy to do? If we have all our scientific truths, are entertained, and know how to do the things we want, what more is there? Well, what about what we should do? Not in an ethical sense, although that is probably a part of it, but in the sense of knowing how to put that know-how and those scientific facts to work serving our interests. Suppose you know how to build a bridge and you now what effects building a bridge in various different places will have. Even so, you still don’t know where to build the bridge; to know where to build a bridge requires additional knowledge concerning what interests you want that bridge to serve and how your choice about where to build the bridge will affect those interests. Of course in many cases such knowledge is trivial; it may be your goal to reduce congestion, and thus no special knowledge is needed for your task beyond what you already have. However, when it comes to our larger goals in life, such as happiness, or making the world a better place, often it isn’t obvious how to put our knowledge to work. This, I claim, is the purpose of philosophy, to provide perspectives using which we can better pursue certain of our interests.
Naturally to make that a plausible description of philosophy will require some more words concerning exactly how philosophy can do just that. But let me bracket that problem for the moment and return to an issue I raised when considering whether we could take philosophy to be a kind of intellectual art form. I pointed out that making such a claim about philosophy would be a drastic break with the history of philosophy, so much that it would be misleading to call the discipline that resulted by the same name. What about the idea that philosophy provides pragmatically useful perspectives? Is it too a radical break? I don’t think that it is, although obviously being a particular idea about the purpose of philosophy in a time when the purpose of philosophy is unclear will result in the judgment that some of what has been called philosophy so far isn’t really, or is rather bad philosophy. In general, though, it doesn’t seem absurd to say that historically philosophy has provided perspectives on issues that at least aimed to be compatible with the relevant facts (although they often fell short, to be expected given that we are learning more about the relevant facts). The only remaining question to ask then is whether philosophy survived because these perspectives were found to be useful. I think historically the answer is yes. Obviously philosophers have always fancied themselves to be after special truths that only they could properly address, but that is simply the philosopher’s conceit. Other people, however, have used the works of philosophers as guides for science, politics, and everyday living, among other things. It was because they were found useful, I claim, that philosophy was perpetuated. And while this may not be true of modern philosophy, at least not so much, this is, I claim, because modern philosophy has strayed from its roots and the real purpose of philosophy. Thus I see my claim that the purpose of philosophy is to provide useful perspectives as being a continuation of the historical practice of philosophy, and thus not a radical break with what we have called philosophy up to now, although it is a break with some of modern philosophy.
Still, much remains to be said. It remains to be said how exactly philosophy can go about serving its purpose. It remains to be said how philosophy can be right or wrong, and thus how we can make sense of philosophical objections and responses. And it remains to be said how, exactly, the various philosophical subfields, such as mind, language, epistemology, and so on might be useful. But it is something that won’t be said today.