This was my lot and my challenge Sept. 12, before a morning class of 40 or so students, many of whom are not yet convinced that philosophy has anything to do with life — let alone life-and-death situations.

Having tried my hand at teaching philosophy for longer than I want to remember, the most persistent and vexing problem I encounter is the allegedly broadminded notion that all ideas are equal. “The deepest definition of youth,” the philosopher Alfred North Whitehead once remarked, “is life untouched by tragedy.” In a fantasy world where terrorists are movie actors and mass death is a special effect, moral ideas do not seem to be particularly important. After all, they are just ideas, harmless abstractions that are essentially unreadable — or, in the terminology of deconstructionists, “undecidable.”

It is imperative, however, that we learn how to read ideas when they are ideas, before some of them have a chance to become explosive. What bad idea may be germinating in our heads right now that will one day bring about, when put into practice, a personal calamity? Wisdom is the virtue of reading moral ideas, then adopting them if they are good and rejecting them if they are evil. The opposite of wisdom is foolishness, the wholly unrealistic notion, made respectable by such self-congratulatory terms as “open-mindedness,” “tolerance” and “broad-mindedness,” that all ideas are of equal value. It is the wise person who sees the good in a good idea, and the evil in one that is evil. We should not want to learn our “practical” ethics the hard way: This is to say, that nothing is more practical than wisdom.

If we have failed in the twin areas of intelligence and security, then we have been humbled. But being humbled is no reason for despair. What emerged from the attack on America was a brotherly love, evidenced by solidarity and sacrifice and heroism, that was as moving as the monstrous assaults were horrifying. Human beings are never more human than when they stand together. As mere individuals, pursuing their own course of self-interest, they are not particularly impressive.

As a teacher, I find nothing more tedious than a student who tries to show how smart he is. Conversely, nothing is more arousing that a student who indicates that he wants to learn. Wisdom is not easy. At best, as the philosopher Jacques Maritain has said, “we are merely beggars at the door of wisdom.” Philosophers, which should include students of “practical ethics,” are lovers of wisdom. To subordinate oneself to something beyond oneself is a sign of humility, which is the path to wisdom. All lovers are wise, and this explains why lovers rise above their paltry state of mere individuality. Love, by binding one person to another or to something higher than oneself, humanizes and exalts. The death of a loved one elicits poignant, but unmistakable, signs of love in the bereaved. Love makes us godlike. Self-concern makes us bores.

We have been chastised. But in our chastisement we find reasons for hope.

We did not know there was so much love. It was bottled up, unexpressed, eclipsed by the practical concern of making a living. And then, in an explosive moment, there were explosions of love. When death strikes, we put things into their proper perspective. The essentials come first — love, companionship — and we're suddenly, acutely aware how much we owe each other. The non-essentials — image, income, industry, individuality — come a far distant second.

Terrorist assaults ripped away our pretenses and exposed our humanity. Can we not find our way to humanity through wisdom, rather than through terror? Philosophy is learning the wise way. But we do not put much of a premium on wisdom these days. Pundit Bill Maher quips that “philosophy is about as useful as a bidet in a gorilla cage.” He is being politically correct and pandering to the times. Philosophy has a knack for burying its undertakers. Yet what it wants to do is enlighten its lovers.

There is a popular television program emanating from Toronto called “Speakers’ Corner,” in which the “man on the street” gets to air his grievances. It has been said that watching this program is the fastest way to lose one's faith in humanity. The endless litany of petty complaints, clumsily stated, of individuals who seem oblivious to life's abundant blessings, turns the show into a farce. There was nothing farcical about the way Americans responded to the events of Sept. 11.

Human beings begin to reveal their dignity and their humanity when they link themselves to something more important than themselves. This is a great paradox — that by losing ourselves, we find ourselves. Adversity need not overcome us. It can show us what we are made of.

In the light of what has happened, all pettiness and self-indulgence seems so much less excusable. Even a calamity brings light. Philosophy is not a game. It matters. Wisdom will avail herself to anyone who has the humility to call upon her. We have been chastised. But in our chastisement we find reasons for hope and the need for reform. Let us resolve to live as if the important things were important and as if wisdom were to be more highly prized than foolishness. Let us not seek to return to “normalcy,” but to advance to authenticity.

Donald DeMarco teaches philosophy at St. Jerome's University in Waterloo, Ontario.