Philosophy is not an optional experience in your life.
"Wow," I thought, "That's true." But what struck me about that statement isn't that it's not optional for me. I've never been able to resist pondering the big mysteries in life. What's striking is that it's not optional for anybody. Nobody can go through life without facing some of life's big questions and deciding how they're going to answer them. Consider the idea of economic justice: the question of who deserves what in society. How you vote depends on how you answer that philosophical question. Is it right to tax wealthier people to give poorer people a bigger slice of the pie? Why or why not? To what extent do the wealthy deserve their wealth? Does it matter whether they inherited it or earned it by being smart and hardworking? If it does, to what extent do people deserve credit for being smart? If some people are simply born smarter, do they deserve to be wealthier based on an accident of birth? Why or why not?
These are all tough questions, which is why people still argue about them. And they're just some of the philosophical questions we can't avoid, either individually or as a society. On the individual level, suppose a friend asks what you think about his new, expensive car. You think it might be the ugliest thing on four wheels. Should you be honest, or should you tread lightly on his ego and say it's great, since he can't return it anyway? That's a philosophical issue, but a fairly trivial one. Most of us will have to face far bigger ones someday. For example, we may have to decide whether a dying family member should be taken off life support. That's not idle dorm room philosophy. How you decide that particular philosophical issue is literally a matter of life and death. Even if you believe the right answer is provided by religion, and can be looked up in the Bible, you still have to weigh philosophical issues. How do you decide which interpretation of the Bible is correct, or example? If different Christian denominations have different answers, how do you decide which one is right? If a non-Christian asks you why he should accept what the Bible says, how do you respond? It won't do any good to say, "Because the Bible says so." You need to provide independent reasons. In other words, you're back to philosophy.
Actually, though, maybe it's not philosophy that's not optional. What's really not optional is facing big philosophical questions and making decisions about them. Actually engaging in philosophy--in hard thinking about those questions--might be optional, because some people make decisions without thinking. They may never question their intuitions, or just automatically apply rules from the ideology, culture, or religion they grew up with. We can't avoid facing life's big questions, but we can avoid really thinking about them, if that's what we really want to do. But most people, I hope, don't really want to do that. Most people like to think they can back up their opinions with solid reasons for believing them.
But oftentimes, they can't. They think what they think because they grew up thinking it, or because their friends or family think that way, or because they just feel in their guts that one answer is right. Those clearly aren't adequate reasons, because they can all lead to false beliefs. Some people "just know in their guts" that men are superior to women. Their guts are wrong. Young Vikings grew up believing that Thor caused thunderstorms. They grew up mistaken. Their dear old Viking mamas and daddies were wrong.
This means that if we want to be able to back up our opinions with real reasoning, not just appeals to authority, tradition, or gut feelings, that's when philosophy isn't optional. That's why people need to learn a little about philosophy, because philosophers really have clarified some of these questions. To take a currently contentious example, many people who oppose gay marriage do so based on two arguments 1. God says it's wrong, as shown in certain Bible verses 2. It's not natural (it goes against the laws of nature or God's plan). The first is the Divine Command theory of ethics, and the second is a Natural Law theory. But here's the thing--philosophers have discovered serious logical problems with both of those theories, which have caused most to abandon them. The Divine Command theory runs into the Euthyphro Dilemma, and Natural Law arguments run into many objections, one of which is: Who says what's natural is good? Many male mammals kill babies of their species who aren't theirs. Does that mean infanticide is right?
The fact that philosophers have mostly rejected Divine Command and Natural Law theories of ethics doesn't mean those theories are wrong, but it does mean it's worth taking a critical look at both of them. If you want to defend either one adequately, you need to know what the objections are. They may not be convincing to you, but they certainly aren't trivial. Some of those philosophers were pretty smart people, after all, and some of the big questions they've wrestled with are questions we can't avoid. It might be possible to avoid thinking about those questions--to avoid doing philosophy, in other words--but it certainly isn't wise. If we want to be able to say our beliefs about some of life's most crucial questions are based on solid reasoning, then philosophy just isn't optional.