The standard account of the reasoning process within geology views it as lacking a distinctive methodology of its own. Rather, geology is described as a derivative science, relying on the logical techniques exemplified by physics. I argue that this account is inadequate and skews our understanding of both geology and the scientific process in general. Far from simply taking up and applying the logical techniques of physics, geological reasoning has developed its own distinctive set of logical procedures.
I begin with a review of contemporary philosophy of science as it relates to geology. I then discuss the two distinctive features of geological reasoning, which are its nature as (1) an interpretive and (2) a historical science. I conclude that geological reasoning offers us the best model of the type of reasoning necessary for confronting the type of problems we are likely to face in the 21st century.