We can act as if there were a God; feel as if we were free; consider Nature as if she were full of special designs; lay plans as if we were to be immortal; and we find then that these words do make a genuine difference in our moral life.
The old question of whether there is design is idle. The real question is what is the world, whether or not it have a designer--and that can be revealed only by the study of all nature's particulars.