Tautological assertions

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http://en.wikipedia.org/wiki/Objections_to_evolution

But he insists that we view scientific theories as consisting of an “elaborate collection of statements,” some of which are not falsifiable, and others – what he calls “auxiliary hypotheses,” which are. According to Kitcher, good scientific theories must have three features – unity, fecundity, and independent testability of auxiliary hypotheses:

Unity “A science should be unified .... Good theories consist of just one problem-solving strategy, or a small family of problem-solving strategies, that can be applied to a wide range of problems” (1982: 47).

Fecundity A great scientific theory, like Newton’s, opens up new areas of research... Because a theory presents a new way of looking at the world, it can lead us to ask new questions, and so to embark on new and fruitful lines of inquiry... Typically, a flourishing science is incomplete. At any time, it raises more questions than it can currently answer. But incompleteness is no vice. On the contrary, incompleteness is the mother of fecundity... A good theory should be productive; it should raise new questions and presume that those questions can be answered without giving up its problem-solving strategies (1982: 47–48).

Auxiliary hypotheses that are independently testable “An auxiliary hypothesis ought to be testable independently of the particular problem it is introduced to solve, independently of the theory it is designed to save” (1982: 46) (e.g. the evidence for the existence of Neptune is independent of the anomalies in Uranus’s orbit).

Like other definitions of theories, including Popper’s, Kitcher makes it clear that a good theory includes statements that have (in his terms) “observational consequences.” But, like the observation of irregularities in Uranus’s orbit, falsification is only one possible consequence of an observation. The production of new hypotheses is another possible – and equally important – observational consequence. Kitcher’s account of a good theory is based not only on his understanding of how physical sciences work. He is also taking into account the way the life sciences work.

From Kitcher’s point of view, Darwinian theory not only meets the three conditions for a good scientific theory; it is without question an extraordinarily successful theory: The heart of Darwinian evolutionary theory is a family of problem-solving strategies, related by their common employment of a particular style of historical narrative. A Darwinian history is a piece of reasoning of the following general form. The first step consists in a description of an ancestral population of organisms. The reasoning proceeds by tracing the modification of the population through subsequent generations, showing how characteristics were selected, inherited, and became prevalent. Reasoning like this can be used to answer a host of biological questions.[76]

The same kind of story can be told again and again to answer all sorts of questions about all sorts of living things. Evolutionary theory is unified because so many diverse questions ... can be addressed by advancing Darwinian histories. Moreover, these narratives constantly make claims that are subject to independent check.[77] Darwin not only provided a scheme for unifying the diversity of life. He also gave a structure to our ignorance. After Darwin, it was important to resolve general issues about the presuppositions of Darwinian histories. The way in which biology should proceed had been made admirably plain, and it was clear that biologists had to tackle questions for which they had, as yet, no answers.[78]