Modes of research in genetics / by Raymond Pearl.

  • Raymond Pearl
Date:
1915
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Modes of research in genetics / by Raymond Pearl. Source: Wellcome Collection.

    42/204 page 30
    30 MODES OF RESEARCH IN GENETICS consequences of a particular hypothesis with the observed data does not prove, in the absence of an¬ other kind of evidence, that the hypothesis ex¬ presses the causal basis of the phenomena. If an hypothesis is true its numerical consequences must accord with observation : but the converse proposi¬ tion that because there is agreement the hypothe¬ sis must be true, does not necessarily follow. It is one of the weaknesses of the human mind to fall into the error of thinking that it does : it is a mis¬ take most of us have made in one form or another.^ Bateson's reduplication hypothesis seems to furnish an excellent concrete illustration of the point. Essentially the only evidence in favor of the hypothesis is that derived from the agreement between observed and expected statistical ratios. This is totally inadequate to base any cytological hypothesis upon. Some other kind of evidence must be forthcoming before it can be demonstrated that some gametes reduplicate to a just-suffi¬ cient degree to meet the exigencies of the case. An ingenious mathematician could probably frame ^ One learns to be cautious about expectations. There once came to my attention some results put together by a non-mathe¬ matical biologist, who had elaborated a very complicated mathe¬ matical hypothesis to account for his observations. The agreement was wonderfully close between observed and expected. Some of its significance disappeared, however, when it was found, upon analysis of the hypothesis, that the mathematical methods involved were such that, barring an arithmetical error, there could by no pos¬ sibility ever be more than a fractional discrepancy between observation and calculation, whatever the nature of the observations !
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