In my last post I gave some details from the first two chapters of Rüdiger Safranski's book on the friendship between Goethe and Schiller. In the early chapters, where there is no friendship as yet, but only a one-sided admiration for the other (on Schiller's part) or disapproval (of Goethe toward Schiller, when he became aware of his existence at all), Safranski portrays common aspects of their lives and pursuits that will make it possible for them to become friends in the 1790s.
Besides the effect on both of them of "court" culture, both men were intensely occupied with the concept of "nature." For Goethe, his essays on Gothic architecture and Shakespeare from the early 1770s had nature as their theme. These essays had an immense impact on Schiller and his cohort.
"Nature" is of course a very big concept, one that has occupied thinkers from the pre-Socratics onward, but for most of history it was probably not one that occupied ordinary folks, for whom the natural world and their own individual nature were part of a larger plan of a world for which they had been created by an omniscient God. In the 17th century, however, with discoveries in astronomy and in the workings of the human body, the certainty about man's individual destiny in God's creation was put in doubt.
In the face of growing philosophical materialism in the 18th century, thinkers and artists struggled to replace the lost dignity of the human person. What can be the importance of humans within a universe with billions of stars? (What would even Isaac Newton have made of the spectacular cluster globular cluster Omega Centauri, one of the biggest and most massive of 200 globular clusters orbiting the Milky Way, glittering with 10 million stars?)
Goethe's "organic" concept of nature was one in which humans were an integral part of the same organicism that produced the growth of the flowers and all that was growing and vital on the earth. In turn, works of art reflected this organicism, having been created by an artist responding to the promptings of his own nature. Anything that limited or deformed this natural facility was therefore "unnatural." We are all familiar with the terminology, from Rousseau on, and young men in Schiller's generation were in particular opposed to all the supposed "unnatural" influences represented by society, including social conventions. At the same time, Goethe's concept of nature was an ambivalent one: after all, nature has two sides, one constructive, another destructive.
Schiller had imbibed these insights, especially the implications of determinism. Because of his medical studies he also no doubt came face to face with the issue of materialism. Safranski mentions that he attended a dissection of a corpse, for which he wrote a report. The description is rather revolting -- the deceased must have been horribly diseased -- and it ends as follows: "The head was not opened." From this early time, it became a preoccupation for Schiller to discover some principle that explained why humans were free agents. His play The Robbers thematizes the issue: both Franz and Karl Moor seem determined by their basic natures to be bad or good, respectively. In the end, however, Karl makes a choice that establishes his freedom, even though it means he will go to prison.
Schiller, unable to accept a purely materialist explanation of human behavior, was at this stage already seeking to carve out a realm of freedom for man, which would be represented in his late essays. In the first (and only surviving) chapter of his medical thesis, from 1781, he introduced what Safranksi calls a "Mittelkraft" -- a mediating power -- into the "Körperwelt" (physiology) that bridges the gap between body and soul, spirit and reason. At his point, according to Safranski, this power was love.
Interestingly, not many years after Schiller's dissection of human bodies, Goethe began his own studies in natural sciences, which included examination of rhino horns and elephant skulls. In 1784, he obtained the "skull of an embryo" in which he discovered a mediating element, namely, the intermaxillary bone (pictured here in his own drawings). This bone, though found in other mammals, had always appeared to be absent in humans. There has been controversy about whether Goethe was actually responsible for this discovery or, indeed, whether it was an important discovery at all, but for Goethe it established that humans were not sui generis but were connected with, well, apes and other mammals. Some people have concluded from this that Goethe was a Darwinist, avant la lettre. Robert Richards comes pretty close to that conclusion, though other scholars of the history of science are more nuanced.