Stephen Jay Gould, from Wonderful Life pp. 277-282:
Beyond a platitudinous appeal to open-mindedness, the “scientific method” involves a set of concepts and procedures tailored to the image of a man in a white coat twirling dials in a laboratory–experiment, quantification, repetition, prediction, and restriction of complexity to a few variables that can be controlled and manipulated. These procedures are powerful, but they do not encompass all of nature’s variety. How should scientists operate when they must try to explain the results of history, those inordinately complex events that can occur but once in detailed glory? Many large domains of nature–cosmology, geology, and evolution among them–must be studied with the tools of history. The appropriate methods focus on narrative, not experiment as usually conceived.
The stereotype of the “scientific method” has no place for irreducible history. Nature’s laws are defined by their invariance in space and time. The techniques of controlled experiment, and reduction of natural complexity to a minimal set of general causes, presuppose that all times can be treated alike and adequately simulated in a laboratory.
. . .
Historical explanations are distinct from conventional experimental results in many ways. The issue of verification by repetition does not arise because we are trying to account for uniqueness of detail that cannot, both by laws of probability and time’s arrow of irreversibility, occur together again. . . . And the issue of prediction, a central ingredient in the stereotype, does not enter into a historical narrative. . . .
These differences place historical, or narrative, explanations in an unfavorable light when judged by restrictive stereotypes of the “scientific method.” . . .
Perhaps the saddest aspect of this linear ranking lies in the acceptance of inferiority by bottom dwellers, and their persistent attempt to ape inappropriate methods that may work higher up on the ladder. . . .
Thus, historical scientists often import an oversimplified caricature of “hard” science, or simply bow to pronouncements of professions with higher status. Many geologists accepted Lord Kelvin’s last and most restrictive dates for a young earth, though the data of fossils and strata spoke clearly for more time. (Kelvin’s date bore the prestige of mathematical formulae and the weight of physics, though the discovery of radioactivity soon invalidated Kelvin’s premise that heat now rising from the earth’s interior records the cooling of our planet from an initially molten state not long past.) . . .
The firm requirement for all science–whether stereotypical or historical–lies in secure testability, not direct observation. We must be able to determine whether our hypotheses are definitely wrong or probably correct (we leave assertions of certainty to preachers and politicians).