James returned to the United States and finally obtained his medical degree from Harvard in 1869 at the age of 27. After graduation, however, James’s health deteriorated further, and he became deeply depressed. Apparently, one reason for his depres- sion was the implications of materialistic physiology and psychology that had so impressed him. It was clear to James that if the materialism was correct, it applied to him as well. This meant that anything that happened to him was beyond his control. His depression, for example, was a matter of fate, and it made no sense to attempt to do anything about it. James’s acceptance of Darwin’s theory of evolution exacerbated the problem. In Darwin’s view, there is variation, natural selection, and survival of the fittest; there is no freedom or choice.
A major turning point in James’s life came when he read an essay on free will by Charles-Bernard Renouvier (1815–1903). After reading this essay, James (1920) wrote in his diary:
I think that yesterday was a crisis in my life. I finished the first part of Renouvier’s second “Essais” and see no reason why his definition of free will—“The sustaining of a thought because I choose to when I might have other thoughts”—need be the definition of an illusion. At any rate, I will assume for the present—until next year—that it is no illusion. My first act of free will shall be to believe in free will. … Hitherto, when I have felt like taking a free initiative, like daring to act originally, without carefully waiting for contempla- tion of the external world to determine all for me, suicide seemed the most manly form to put my daring into; now I will go a step further with my will, not only act with it, but believe as well; believe in my individual reality and creative power.