What is Philosophy?

The Nature of Philosophy

The word philosophy literally means love of wisdom;1 this tells us something about the nature of philosophy, but not much because many disciplines seek wisdom. How does philosophy differ from these other disciplines? A brief look at the historical development of the field will help us to answer this question.

On the standard way of telling the story, humanity’s first systematic inquiries took place within a mythological or religious framework: people sought wisdom from sacred traditions or from individuals who were thought to have special access to a supernatural (and presumably honest and infallible) realm; no one questioned the legitimacy of these traditions or individuals. However, starting in the sixth century BCE, there appeared in ancient Greece a series of thinkers whose inquiries were comparatively secular (see “The Milesians and the Origin of Philosophy“).2 Supposedly, these thinkers conducted their inquiries by relying on reason and observation instead of tradition or revelation. For this reason, they are considered the first philosophers. Although this picture is simplistic, the basic distinction has stuck: philosophy in its most basic form is nothing less than secular inquiry itself.3

But there now are many forms of secular inquiry, so what distinguishes philosophy from them? In the beginning there was no distinction. But as civilization advanced two parts of philosophy became so powerful in their own right that they separated off, claiming for themselves the status of independent disciplines. Mathematics was the first. Science (or natural philosophy, as it was called into the nineteenth century) was the second. To modern philosophy is left whatever questions these two disciplines cannot solve at a given time. These questions include:

  • Questions that traditionally are thought to be outside the scope of the two, such as “What is the meaning of life?”
  • Theoretical questions at their fringes, such as “Is mathematics reducible to logic?” and “Which interpretation of quantum mechanics is most plausible?”
  • Conceptual questions at their foundations, such as 
    “What are numbers?” and “What is science?”

Philosophy, of course, is best known for the first class of questions, which includes some of the most difficult and important questions there are: questions such as whether or not there is a god, how one can know anything at all, and how a person ought to live.

Philosophy is characterized as much by its methods as by its subject matter. Although philosophers deal with speculative issues that generally cannot be investigated by experimental test, and philosophy therefore is more fully conceptual than science, philosophy properly done is not mere speculation. Philosophers, just like scientists, formulate hypotheses which ultimately must answer to reason and evidence.4 This is one of the things that differentiates philosophy from poetry and mysticism, despite its not being a science.5

The Branches of Philosophy

The four main branches of philosophy are logic, epistemology, metaphysics, and axiology:

Logic is the attempt to codify the rules of rational thought. Logicians explore the structure of arguments that preserve truth or allow the optimal extraction of knowledge from evidence. More formally, logic is the study of the structure of arguments. Logic is one of the primary tools philosophers use in their inquiries. The precision of logic helps philosophers to cope with the subtlety of philosophical problems and the often misleading nature of conversational language.

Epistemology is the study of knowledge itself. Epistemologists ask, for instance, what criteria must be satisfied for something we believe to count as something we know, and even what it means for a proposition to be true. Two epistemological questions I discuss elsewhere on this site are the question of how we can know the future will be like the past, and the question of how we can be sure about anything at all.

Metaphysics is the study of the nature of things. Metaphysicians ask what kinds of things exist and what they are like. They reason about such things as whether or not people have free will, in what sense abstract objects can be said to exist, how it is that brains are able to generate minds, and whether or not there is a god.

Axiology is an umbrella term for different studies that center upon the nature of different types of value.6 These different studies include aesthetics, which investigates the nature of such things as beauty and art; social philosophy and political philosophy; and, most prominently, ethics, which investigates both the nature of right and wrong and the nature of good and evil. Ethics asks theoretical questions about the foundations of morality, such as whether right and wrong should be understood in a consequentialist or deontological way, but also asks practical questions about the fine details of moral conduct, such as how much moral consideration one ought to give to non-human animals and how much one ought to give to the poor.

Many professional philosophers also double as historians, researching one or another aspect of the history of philosophical thought. Even those who do not conduct novel historical research typically study the texts of thinkers as far back as the ancient Greeks for both philosophical insight and enjoyment. Arguably, history of philosophy is a fifth branch of philosophy.

There also are many “little” branches of philosophy (some of them truthfully quite huge) which address problems and questions that relate to  other specific disciplines. There are, for instance, philosophers of religion, philosophers of psychology, philosophers of biology, and (like me) philosophers of physics.

As you can tell, the different branches of philosophy overlap one another. A philosopher considering how much one ought to give to the poor is asking an ethical question. However, his investigations might lead him to wonder whether or not standards of right and wrong are built into the fabric of the universe—a metaphysical question. If he claims that people are justified in taking a particular stance on that question, he is making an  epistemological claim. At every step in his reasoning, he will want to use logic to minimize the chance of being led into error by the great complexity and obscurity of the questions. He may very well look to some of the ethical, metaphysical, and epistemological writings of past philosophers to see how his brightest predecessors reasoned about the matter.

Aspects of each branch of philosophy can be studied in isolation, but philosophical questions have a way of leading to other philosophical questions. A full investigation of any particular problem is likely eventually to involve almost the whole of the philosophical enterprise.

The Demands of Philosophy

Philosophical inquiry is very demanding, suitable only for those who possess a modest amount of courage, humility, patience and discipline.

Doing philosophy requires courage because one never knows what one will find at the end of a philosophical investigation. Since philosophy can deal with the most fundamental and important aspects of human existence and since these are things that most people initially take for granted, genuine philosophical inquiry has the potential to unsettle or even to destroy one’s deepest and most cherished beliefs. To engage in genuine philosophical inquiry also is to risk isolation among one’s peers, both for the unorthodox views to which such inquiry may lead and for the simple unpopularity of critical thinking. A philosopher must be able to face both consequences.

Doing philosophy requires humility because to do philosophy one must always keep firmly in mind how little one knows and how easy it is to fall into error. The very initiation of philosophical inquiry requires one to admit to oneself that one may not, after all, have all of the answers.

Doing philosophy requires both patience and discipline because philosophical inquiry requires long hours of hard work. One must be prepared to commit huge amounts of time to laboring over issues both difficult and subtle. People who avoid philosophy often complain that thinking about philosophical questions makes their heads hurt. This is unavoidable: if the answers seem to come easily to you, your inquiries almost certainly are superficial. To do philosophy one must commit oneself to pain. Those who value truth recognize that there is no shortcut to it: every advance must be fought for tooth and nail.

These virtues always are imperfectly represented in any given person. This is why philosophy, like science, is best done in a community: the critical scrutiny of other thinkers provides a necessary check on personal defects invisible to one’s own eyes.

The Rewards of Philosophy

But if philosophy is so demanding, why should anyone even bother with it?

In the first place, there is great utility in philosophical inquiry, even for someone who does not innately care about the pursuit of truth. Consider a random handful of classic philosophical questions: What is the meaning of life? What is the nature of justice? What does it take for a belief to be justified? Is the world we see illusion or reality? The answers to such questions cannot help but to have a critical impact on how one ought to live one’s life. Surely one should subject one’s intuitive beliefs about these things to critical scrutiny and work hard to come as close to truth as possible. Many philosophical questions are fundamental to human life; the only reason they often seem irrelevant is that most people tend simply to assume they know what the answers to these questions are without ever daring to make a serious inquiry.

This leads us to the second reason to do philosophy: to understand is ennobling. Simply to assume one understands is not. To be sure, a person who never questions anything might live happily—at least in the same way that a well-fed dog lives happily. Philosophy, on the other hand, can be disquieting, as there is no guarantee that one’s philosophical investigations will lead to the conclusions one hopes for. Worse, they may not yield any conclusion: at the end of the day, one may find oneself stripped of the certainties with which one began, and without new ones to put in their place. Doing philosophy may require one to live in perpetual uncertainty while others, in their ignorance, happily profess perfect knowledge. But it is clear who has the better life: far better to understand, even if what one understands is the limit of one’s own knowledge.

A final reason for studying philosophy is that, for all of the pains and difficulties associated with it, the pursuit and acquisition of knowledge is enjoyable. To be sure, it is a refined enjoyment and from the outside it is often hard to see what the appeal is. But once one becomes immersed in it, it carries its own immediate rewards and even becomes addictive. I have experienced most of the same pleasures everyone else has, but in the end none of them hold a candle to the pleasures of the mind—to the sheer pleasure of studying and investigating, and sometimes even understanding.


1 From the Greek philia (friendship/love) or philos (friend/lover) and sophia (wisdom). According to the admittedly unreliable Diogenes Laertius (Lives and Opinions of Eminent Philosophers, I.VIII), the term philosopher was introduced by Pythagoras, who supposedly preferred it to the less modest title of sophist, or “wise man.”

2 The standard story, wherein the Milesians literally are the first secular thinkers, cannot literally be true; it is scarcely possible that human thought could have been uniformly superstitious—broadly, yes, but not uniformly—at any time in history. However, we have no formal record of the Milesian style of thought prior to the “official” advent of philosophy.

3 To say that philosophy is secular does not mean that it is anti-religious, but only that it is independent of religion. If one needed to be anti-religious or even nonreligious to do philosophy, the history of philosophy would be very slim. To say that philosophy is secular also is not to deny that there are many thinkers, arguably including most of the first philosophers themselves, for whom it is not always clear whether they are doing philosophy or theology: philosophy, like any other discipline, has gray boundaries.

4 In saying this, am I ruling out Continental philosophy by stipulation? I don’t think so, at least not across the board. To be sure, Continental philosophers do not write like analytic philosophers, and I consider that a vice, but I am not sure that their rock-bottom commitments are different from those of analytic philosophers. The phenomenologists and existentialists I am familiar with seem to base their thought upon rational and evidential grounds as much as anyone else; even with postmodernists, I am not sure that the open disdain for reason and evidence is more than just talk. Am I ruling out from philosophy anyone whose inquiries do not ultimately rely upon reason and evidence? Yes, with no apologies.

5 I need to make another qualification here: poetry and literature sometimes can overlap with philosophy. Camus, for instance, expressed himself very well through the medium of novels and plays, but he seems to have worked out those thoughts by using to reason and evidence. I would contrast that with, say, the poem by Whitman that expresses disgust with the way astronomers dissect nature, and contrasts their efforts with the beauty of the night sky. I suspect Whitman was just articulating feelings rather than a position he had worked out rationally: however deep his feelings might be, and however much grist they might provide for a philosophical mill, Whitman still was not doing philosophy.

6 Some philosophers use the term axiology in a more constrained (and perhaps more proper) way, to refer strictly to the study of questions of value; in such usage, axiology cuts across the studies I list, functioning as a component of each rather than an umbrella term for all.

Suggested introductory books

Lawhead WF. 2015. The Voyage of Discovery: A Historical Introduction to Philosophy: Fourth Edition. Belmont, CA: Wadsworth.

This is a historical introduction to philosophy that I use in my current Philosophy 101 classes. It is very well-written and consists almost entirely of secondary text, with only a few pages per chapter of original text.

Nagel T. 1987. What Does It All Mean? Oxford: Oxford University Press.

So far, this is the only topic-oriented general introduction to philosophy that I really like. It is very short and does not address some key questions, but it is a great first step.

Stumpf SE, Fieser J. 2007. Socrates to Sartre and Beyond: Eighth Edition. New York: McGraw-Hill.

This is another historical introduction that I used to use in my Philosophy 101 classes. It is considerably denser than Lawhead, which may be good or bad depending on your temperament.

Warburton N. 2006. Philosophy: The Classics: Third Edition. New York: Routledge.

This is yet another historical introduction that I used to use in my Philosophy 101 classes. Each chapter covers, in lightning speed, one book by one philosopher. This is a great first step into the history of philosophy. Warburton also offers free audio versions of most of the chapters.