Another example of reason's incapacity to lead to moral conclusions: On virtually any vexing moral question, there is no such a thing as a [missing] purely rational viewpoint. What is the purely rational view on the morality of abortion? Of public nudity? Of the value of an animal versus that of a human? Of the war in Iraq? Of capital punishment for murder? On any of these issues, reason alone can argue effectively for almost any position. Therefore, what determines anyone's moral views are, among other things, his values -- and values are beyond reason alone (though one should be able to rationally explain and defend those values). If you value the human fetus, most abortions are immoral; if you only value the woman's view of the value of the fetus, all abortions are moral.
The second problem with reason alone as a moral guide is that we are incapable of morally functioning on the basis of reason alone. Our passions, psychology, values, beliefs, emotions and experiences all influence the ways in which even the most rational person determines what is moral and whether to act on it.
Third, the belief in reason alone is itself based on an irrational belief -- that people are basically good. You have to believe that people are basically good in order to believe that human reason will necessarily lead to moral conclusions.
Fourth, even when reason does lead to a moral conclusion, it in no way compels acting on that conclusion. Let's return to the example of the non-Jew in Nazi-occupied Europe. Imagine that a Jewish family knocks on his door, asking to be hidden. Imagine further that on rational grounds alone (though I cannot think of any), the non-Jew decides that the moral thing to do is hide the Jews. Will he act on this decision at the risk of his life? Not if reason alone guides him. People don't risk their lives for strangers on the basis of reason. They do so on the basis of faith -- faith in something that far transcends reason alone.
Does all this mean that reason is useless? God forbid. Reason and rational thought are among the hallmarks of humanity's potential greatness. But alone, reason is largely worthless in the greatest quest of all -- making human beings kinder and more decent. To accomplish that, God, a divinely revealed manual and reason are all necessary. And even then there are no guarantees.
But if you want a quick evaluation of where godless reason leads, look at the irrationality and moral confusion that permeate the embodiment of reason without God -- your local university.
Dennis Prager is a SRN radio show host, contributing columnist for Townhall.com and author of his newest book, “The Ten Commandments: Still the Best Moral Code.”