The world is a complicated place, and we are not psychologically equipped to handle its complexity. It is possible to give a complete description of the human body in terms of the particles that compose it, their states, and velocities. But, while such a description doesn’t leave anything out, it isn’t medically useful, for example. Sure, by knowing the positions of all those particles you could eventually work out how the body in question would change over time, and what effect making alterations to it would have. But by the time that you did that your patient would be long dead of old age. What is medically useful is a higher level of description, one that describes the body in terms of it major systems and their current state, as well as a list of chemicals and the effects they have on those major systems. With such a description it is easy to detect abnormalities and to determine the correct course of treatment. Now obviously this higher level of description isn’t independent from the facts about all of the body’s particles; indeed the higher level description could have been derived by abstraction from those facts. But when it comes to actually getting something done it is often the higher level of description that is desired, even though it leaves information out.
And this is true of life in general. What we need to get around and to accomplish are goals are appropriate high level descriptions; ones that contain only the facts pertinent to our goals and which omit unnecessary detail. For example, when you think about your bank account you conceive of it as a collection of money that you can pull sums out of. But of course physically your bank account is a complicated affair involving a number of databases, and the process of “pulling sums out of it” is a complicated electronic transaction involving all sorts of security measures. But having to think about all those facts whenever you considered whether to withdraw money from the ATM to pay for lunch would be a hindrance, and so you are better served by the abstraction of your bank account as a collection of money. The abstraction is a tool for getting things done, even if it isn’t a perfect representation of reality, and a perfect representation would be an inferior tool.
Something else to note about these higher levels of description is that what makes for a good one is determined by two things. One is the underlying facts about the matter at hand; a description that sufficiently mischaracterizes what is actually occurring will be misleading, and hence a hindrance. The other is the goals of the person employing the description. Someone working with the banking system, for example, would want to work with a description of bank accounts that captures more details about them than “a collection of money” does. That difference is one of an amount of detail. But it is also possible that different goals may be served with descriptions that describe the situation in mutually incompatible ways. Consider the way that capitalism is understood both by capitalists and socialists. Capitalists tend to describe the system in terms that capture its ability to efficiently allocate resources and generate wealth as a whole. Socialists, on the other hand, focus on the ways in which there are disparities between roles within the system (for example, the fact that the owner of capital receives more rewards than labor). Both these descriptions are accurate (or can be made accurate, modulo propaganda); they differ because they capture different facts about the system. Capitalists tend to be interested in maximizing the welfare of society as a whole, and so their description captures the way the system is efficient and wealth generating, i.e. system wide properties. Socialists on the other hand are interested in reducing inequality, and so their description of the system captures the way in which different kinds of people are affected by it. If one of these two groups is wrong it is not that they are inaccurately describing the system (at least necessarily), rather it must be the case that their description is emphasizing the wrong facts about the system, those that aren’t the most important when it comes to evaluating it. (Taking a neutral perspective we could instead say that each group’s description emphasizes the facts that they make judgments about value based on.)
I propose that these higher level descriptions, designed to serve some particular goals, are what philosophy should aim to produce. Although in philosophy we wouldn’t call them descriptions, but rather theories or perspectives. Of course not every high level description counts as philosophy; a medical perspective on the human body or a practical perspective on the banking system do not count as philosophy, for example. The distinction between the two lies, I think, in the degree to which the goals that the description is meant to serve vary. Everyone, or almost everyone, has a vested interest in keeping the human body working and in being able to comfortably deal with their ATM. Thus there is, in a sense, an objectively correct way of describing those systems with respect to these nearly universal goals. Or, perhaps in the case of medicine, it would be best to say that everyone with an interest that requires a description at that particular level of detail about the topic shares the same goals. In contrast philosophical perspectives/theories constitute descriptions that serve goals that not everyone has, and more importantly, some people have orthogonal or conflicting goals that are best served by different descriptions. The descriptions of capitalism and socialism described above are examples of such a philosophical perspective. People disagree about what is important in an economic system and so different descriptions at roughly the same level of detail are needed to serve these different ends.
In a way then philosophy, construed as such, might be considered a kind of opinion. After all when goals differ often we are in no position to say that some of those goals are in error. And thus it is a matter of opinion as to which philosophical perspective is best since it is a matter of opinion which goals we should have (setting aside any theories about which goals we should have relative to our other goals). But, on the other hand, there is an objective matter of fact about the correctness of any particular philosophical perspective, namely how well it serves the goals it was designed to. It is possible to compare two philosophical perspectives about the same topic designed with the same goals in mind and see how well they help fulfill those goals in comparison to each other, empirically if need be. Thus philosophical perspectives live on the border between fact and opinion, and contain a mixture of both.
Allow me to give an example of this principle in action by describing three philosophical perspectives on the nature of color. There are three common theories about what color is. One is that color is part of the phenomenal world (1), that an object being a particular color is to be identified with it causing a certain kind of experience. Thus, under this theory, when it is dark all objects are black, shining a red light on a normally white wall makes the wall red, and in cases of color illusions (such as the apparent changes of color in response to changes in background color) the actual color is being changed. Another perspective is one that identifies color with the light reflected by an object (2). In this case the object’s color is determined by wavelength and number of the photons bouncing off of it. This perspective makes the same judgments as the previous one, except that in the case of color illusions it claims that we are misperceiving the color that is really there. The third perspective is a biological/teleological one (3). Under this perspective a color is identified with a class of surfaces. This can be justified by noting that the way the visual system works to give us color experience (including “illusions” stemming from changes in background) are ways, in normal situations, of matching color to types of surfaces. This is because what matters for survival is not what light is reflected off an object but what object is reflecting the light, and information about the surface itself is most useful in making that judgment. Under this perspective a white wall is still white even when it is illuminated with red light, or when it is completely dark, and color illusions are cases where we are misperceiving color.
None of these theories is an objectively correct or incorrect theory about color. Each of them rests on certain facts about color dealing with the nature of reflected light, the visual system, and correlations with experienced qualia. These facts constrain the perspectives we can propose, but all three perspectives cohere with those facts. Choosing a perspective thus depends on something more, namely what we need a theory of color for. If we are engineers or physicists theory (2) will probably be the most useful. In such situations talk of color often is involved in situations where the discussion is about the spectrum of a star (to determine its age and composition) or where light of certain wavelengths will trigger or be the sign of some reaction. In such situations color terms are most useful as a shorthand for referring to ranges of wavelengths. On the other hand, if we are artists then we are probably best served by theory (1). It doesn’t matter what is really on the canvas, all that matters is what people perceive when they look at it; whether that perception is an “illusion” in some sense is irrelevant. Finally theory (3) probably best serves our everyday interests when it comes to color as a way of differentiating between objects based on their surfaces. If you want someone to hand you the teal book, for example, you don’t want their judgment to be affected by the fact that it is darker than usual or the fact that the teal book is next to very dark books of the shelf. You want them to hand you the book with that particular cover, and you want to be able to refer to that cover in a way that is essentially invariant with respect to conditions external to the cover of the book.
Philosophical elaboration and refinement of all of these perspectives is thus justified since there are groups to whom each is the superior intellectual tool. We can’t criticize such a perspective by claiming that it is factually in error, since it is not making factual claims; if we criticize it we must do so on the grounds that it systematically hinders the interests of its intended group, that some other perspective better serves those same interests, or that it doesn’t have an intended group. This is the same way that we might criticize an ordinary tool, such as a hammer. We could argue that it is a bad tool if it is systematically deficient, if there is some other tool that does the same job better, or if no one needs that particular tool. But it doesn’t make sense to say that the hammer is “wrong” or that the screwdriver is objectively superior to it. (Although you could argue that the engineering facts, which the effectiveness of the hammer rests on in theory, assuming the hammer has never been tested, are wrong. This would be equivalent to arguing that the facts about the visual system or light that the philosophical perspectives discussed previously rest on are wrong.)
Obviously there are many intricacies of this metaphilosophical perspective left to discuss. However one pressing concern that I will finish with, namely whether this theory undermines itself. This metaphilosophical perspective is itself not something that can be objectively “right”, only useful to a group of people. Thus, it might be argued, the door is left open for other perspectives that contradict this one, which claim that a philosophical theory can be objectively right or wrong, and that seems like it might be a contradiction (since to accept such a perspective would logically necessitate rejecting this one). However, just because the possibility exists doesn’t mean that the theory actually contradicts itself. The problem only arises if for some philosopher it would be useful to reject this metaphilosophical perspective and embrace another. However, I claim that the intended group for this metaphilosophical perspective is philosophers as a whole (under the assumption that they desire philosophy to be useful, anyone who doesn’t care about philosophy being useful, and thus valuable, is someone I think can be justifiably ignored, as I would ignore someone who said they were making tools but didn’t care whether the tools could be used). There is an argument, which I won’t discuss here, that this metaphilosophical perspective is the one that renders philosophy most useful, in comparison to the relevant alternatives. Thus this metaphilosophical perspective is in trouble only if we discover some competing perspective on philosophy that is superior (i.e. that by using it the results of our philosophizing become even more useful/valuable), which is not something that we seem to have at hand (the mere possibility that we might make revisions in the future is not enough). And this is exactly how things should be: the theory does not set itself in stone (it does not try to demonstrate its own necessity); rather it is open to the possibility that improvements may be made. Every theory is provisional (scientific and philosophical alike), and I would be suspicious of any theory that claimed to be otherwise.