Over the past few days Americans have struggled to make sense of the terrorist attack on the World Trade Center and the Pentagon. How did it happen? What could make someone commit such deeds? Why do they hate us? These are some of the anguished questions repeatedly asked by television talking heads, on learned faculty panels and by students in their dining halls and dorm rooms.

In trying to come to terms with last week’s tragedy, a number of explanations have been put forward that seem, to me, to muddy the water rather than clear the air. Below are four ways how not to think about terrorism.

One widely popular explanation is that it is caused by conditions of economic deprivation. The global economy, it is sagely affirmed, has created winners and losers. Terrorists are created by conditions of desperate poverty coupled with the desire for economic justice.

This view is false for two reasons. First it assumes a kind of economic determinism in which terrorism is motivated by a desire for a larger piece of the pie. Economic determinism, let it be said, is a recent and deeply parochial theory of human behavior. This kind of thinking may be flattering to Western egalitarian sensibilities but does not begin to crack the psychology of terrorism. There have always been poor people. Very seldom are they driven to acts of mass murder simply because of poverty alone.

Second, the perpetrators of these actions scarcely fit the portrait of the “wretched of the earth.” They were possessed of education, money and skills. They had passports and the ability to operate under cover. They possibly came from some of the wealthiest regimes in the world. The fact that these regimes are also hopelessly corrupt can scarcely be laid at our door and cannot, therefore, be used as an explanation for acts of terrorism directed against the West.

Another view is that it is American support for Israel that is the cause of terrorism. This view is not only false but insidious. If Osama bin Laden is the genius behind the attack last week, his rage has nothing to do with Israel and the Palestinians but with the American presence in the Persian Gulf.

American support for Israel is often used as a pretext to justify terrorism but is only that — a pretext. Israel is but the furthest outpost of the West in the East. As such it is an endangered and vulnerable outpost. The attack on Israel has nothing to do with it being a Jewish state, but everything to do with it being a Western-style democracy.

The argument that our Israel policy is at the root of the problem is often used as a cloak for bigotry. But there are those who may truly believe that we need to adopt a more “even-handed” approach to Israel and its neighbors. This is tantamount to asking that we be neutral or indifferent to the distinction between dictatorships and democracy. Our policy toward Israel will be an important barometer of our willingness to defend our values and way of life.

The third explanation for the attack, it is claimed, grows out of the nature of religious fundamentalism. This is also misleading. There are many religious fundamentalisms throughout the world. They do not typically sanction the terror bombing of innocent men and women.

Leading authorities claim that terror as well as suicide is forbidden by the Islamic religion. This sounds plausible to me. It is not even clear that the people who carried out the attacks were fundamentalists at all. At least some of them spent their last night on earth at a strip club in Daytona Beach. How fundamentalist could they be?

Finally, it is said that the terror bombing represents a struggle between barbarism and civilization. This is true only up to a point. The attack was not an assault on civilization per se but only on one particular form of civilization — modern civilization composed of democratic political institutions, market capitalism and a broadly secular culture. It is this kind of civilization that the terrorists wanted to destroy. But why, it is still asked, do they hate modernity with such murderous passion?

Professor Paul Kennedy offered an explanation of his own at last Sunday’s “teach-in” at Battell Chapel. Let us consider a “counterfactual” as he called it. Suppose that Islam was a hegemonic world power, and the West divided into so many weak and struggling states. Suppose further that Islam was everywhere spreading its values and beliefs by way of television, music and the movies thus eroding our culture that was powerless to resist.

Would we not come to resist this colossus; would we not come to loathe it; would we not in fact become terrorists ourselves? This example was greeted with enthusiastic applause.

But consider another counterfactual if you will. Suppose that the terror attack had been carried out by the Aryan nation, that they were angry about our multicultural society, our tolerance of homosexuality and gay rights, that they were outraged by the availability of abortion and even saw the compromise on stem-cell research as a betrayal of the right to life.

If this were the case, would we now be hearing calls for a sympathetic understanding of the “other,” that we have to put these Aryan views in “context,” much less that the terrorists’ wrath was a justifiable response to our open secular culture? Of course not. Even to ask these questions is to provide the answer.

My point is not that my counterfactual is the right one and that Kennedy’s is wrong. It is that all such thought experiments are fatuous. They are created to evoke a predetermined and selective moral response from their audience, nothing more. As such their explanatory power is precisely zero.

The truth is that the attack on America is not about anything we have done; it is not this or that policy with which the terrorists disagree. It is an attack on who and what we are as a people and a nation.

It is not even America that the terrorists hate. It is America insofar as it represents modernity in all of its aspects. The terrorists’ war is a war against modernity. This is why even well-meaning efforts to alleviate global poverty or shamefully abandon an ally will not end terror but exacerbate it. It would only demonstrate our weakness and lack of confidence.

The only justifiable response to the attack is a firm and resolute affirmation of American will, power and intelligence. What Abraham Lincoln said almost 140 years ago was as true then as it is now: “The fiery trial through which we pass will light us down in honor or dishonor to the latest generation — We shall nobly save, or meanly lose, the last best hope of earth.”

Steven B. Smith is Alfred Cowles professor of political science and master of Branford College.