At first glance, the title seems to be a bit contradictory. Isn't art "supposed" to be nonrational? Isn't that the point? These questions are what this essay aims to reconsider. It is a wide topic indeed, and widely covered as well. Here, the author will offer a few thoughts about rationality in general, and point out a possibly fruitful direction of thinking about art in the terms of rationality. To do this, he will compare art with the cultural enterprise that is widely regarded as the truly rational one--science. One of the twentieth century's characteristic features is that art and science have come to be seen as somewhat diametrically opposed. If the scientific enterprise is generally considered to be the hallmark of rational thought, as is the case in modern Western culture, then essentially nonscientific enterprises, like art (and religion, for that matter) would be generally considered to be nonrational. He wishes to suggest that this is basically what happened, and that it is a mistake. He will focus on a particular case from the mid-eighteenth century which he believes to be the watershed, the point at which art and science split and went in opposite directions, and then will offer an initial reconsideration of art as a rational activity. (Contains 6 notes.)