If there is any principle of the Constitution that more imperatively calls for attachment than any other it is the principle of free thought; not free thought for those who agree with us, but freedom for the thought that we hate.
There are one-story intellects, two-story intellects, and three-story intellects with skylights. All fact collectors, who have no aim beyond their facts, are one-story men. Two-story men compare, reason, generalize, using the labors of fact collectors as well as their own. Three-story men idealize, imagine, predict; their best illumination comes from above, through the skylight.