Celebrities and Twitterverse Titans define acceptable thought and behavior, and others thoughtlessly follow. Therefore, we need good intellectual defenses, ones that keep us from eating intellectual junk food. To a similar end, Chesterton writes, “Philosophy is merely thought that has been thought out,” and he allows: “It is often a great bore.” But then again, “man has no alternative, except between being influenced by thought that has been thought out and being influenced by thought that has not been thought out. The latter is what we commonly call culture and enlightenment today.”

Philosophy is the effort to think critically about life’s ultimate questions and the basic concepts of reason. Philosophers investigate what exists, what we can know, and what is of value—not in particular, of course, but in a general or theoretical sense. They also examine ideas like time, existence, evidence, cause, effect, truth, and rationality. Everyone’s thoughts and behavior depend on answers to these philosophical questions. In that sense, everyone is an accidental philosopher, at least, if not an intentional one. To live at all is to live by a philosophical belief system.

For this reason, G. K. Chesterton (1874-1936) defended a revival of philosophy in his own day as doubly urgent, even for regular folks who work in ordinary jobs—people who would never think of themselves as distant colleagues of Socrates or Plato. The problem, as Chesterton sees it, is this: if we do not think for ourselves, someone else will, often in ways that we would never accept, especially if we understood the power of ideas and, in that case, other people’s ideas.

So then, Chesterton writes, “The best reason for a revival of philosophy is that unless a man has a philosophy certain horrible things will happen to him.

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