Reason and Nature in the Enlightenment
A lot of times people look for terms to describe pivotal points in history, which can be found in labels such as Renaissance or Enlightenment. But a lot of times labels are just labels. They are merely tips of the larger continuous currents, as Marc Bloch had said it well that historical time is in essence a continuum and also a perpetual change. In this light a careful but unlearned mind sees everything muddles together and becomes indistinguishable. I, for instance, had not been able to tell the philosophical difference between Renaissance humanists and Enlightenment thinkers. That is the nice thing about reading Ernst Cassirer’s book The Philosophy of the Enlightenment (1951), in which he successfully distinguishes the two in his comment on “reason.”
“One should not seek order, law, and ‘reason’ as a rule that may be grasped and expressed prior to the phenomena, as their a priori ; one should rather discover such regularity in the phenomena themselves, as the form of their immanent connection. Nor should one attempt to anticipate from the outset such ‘reason’ in the form of a closed system; one should rather permit this reason to unfold gradually, with ever increasing clarity and perfection, as knowledge of the facts progresses. The new logic that is now sought in the conviction that it is everywhere present on the path of knowledge is neither the logic of the scholastic nor of the purely mathematical concept; it is rather the ‘logic of facts.’ The mind must abandon itself to the abundance of the phenomena and gauge itself constantly by them.” 
Clearly there is a shift from “the love of system for its own sake” to “the value of system,” from Cartesian deduction to factual analysis, from a prior theory to synthesis of the “positive” and the “rational.” Instead of the Decartes’ question “I think therefore I am,” natural science has replaced thought as the source for original certainty, a starting point of everything. [3-9]
Several ramifications to follow up:
- Comparison to what Habermas called “the incomplete project of modernity.”
- (Related to the previous point) A more open-ended definition (or purpose) of “reason” according to Cassirer.
- The bifurcated meanings of Nature in the modern world. On one side there is the cold empiricist nature, the subject of scientific analysis; however it is also at this time that we see the birth of the aesthetic modes of nature, i.e. the theories of the beautiful, picturesque, and sublime.