The illness, weakness, and stupidity, of course, are not natural characteristics of the enslaved people, but artifacts of the repressive environment, which sets up a fundamental conflict between their value scales and the commands of their masters. This praxeological insight sheds light on a point made in the Course Overview (p. 4)—namely, that, even relatively liberal-minded, sympathetic observers of blacks under ante-bellum slavery, such as Jefferson and Lincoln, could not imagine how they could ever achieve full intellectual and moral parity with whites. This failure of imagination, of course, reflected these observers' experience, which was limited to black people under conditions naturally inimical to high human achievement. If these visionaries were subject to such limitations, we too should beware of underestimating the potential capacities of human beings in a society far freer than our own.