In the movie Contact, an astronomer played by Jodie Foster discovers a radio signal with a discernable pattern, a sequence representing prime numbers from 2 to 101. Because the pattern is too specifically arranged to be mere random space noise, the scientists infer from this data that an extraterrestrial intelligence has transmitted this signal on purpose.

The design inference uncovers intelligent causes by isolating the key trademark of intelligent causes: specified events of small probability. Just about anything that happens is highly improbable, but when a highly improbable event is also specified (i.e., conforms to an independently given pattern) undirected natural causes lose their explanatory power. Design inferences can be found in a range of scientific pursuits from forensic science to research into the origins of life to the search for extraterrestrial intelligence.

This essay examines the relation of Darwin's orchids book to a central persuasive flaw in theOrigin: Its inability to give variation sufficient “presence” to break the hold of “design” in the mind of the reader. Darwin characterized the orchids book as “a flank movement on the enemy”; this essay identifies the “enemy” as Paley's natural theology and the “flank” as thetopoi, maxims, and habits of perception that led Darwin's colleagues and contemporaries to see design in nature. Moreover, this essay examines (...) three aspects of rhetorical timing pertinent toOrchids - time askairos, time as adequate duration, and time as transformation - and then relates those features to Robert Cox's Heideggerian logic of repetition, disavowal, and transcendence. The essay concludes with implications of the tactical and temporal aspects of Darwin's reasoning for understanding both the logic of science and of Darwin as a rhetorical artist. (shrink)