We discussed this topic today in our philosophy of science club, and I’m curious what people here would think.
Josh has said the following regarding rules in biology:
Contrast this with what philosopher John Beatty proposed in this paper, called the Evolutionary Contingency Thesis:
All generalizations about the living world:
a) are just mathematical, physical, or chemical generalizations (or deductive consequences of mathematical, physical, or chemical generalizations plus initial conditions), or
b) are distinctively biological, in which case they describe contingent outcomes of evolution.
Mehmet Elgin recasts the thesis as a clearer argument:
- All distinctively biological generalizations describe contingent outcomes of
- Laws are supposed to be more than just contingently true.
- Therefore, distinctively biological generalizations are not laws.
Thus, unlike physics or chemistry, since all biological life that we study arise from contingent evolutionary processes (which would not repeat if rewound the same way), then biologists are not really studying universal laws like Newton’s Law of Gravitation. Instead, they are merely studying generalizations that happen to be true for a very specific set of conditions, and are likely not very applicable to the rest of biology.
Unlike Josh, who seems to still have confidence in rules despite the few exceptions, I have been told by a biologist friend that almost nothing a biologist finds is applicable outside of the narrow domain in which it was found in the first place. The example she gave was Mendelian genetics: supposedly, we used to think that Mendelian genetics held true for all organisms with genes. However, we then discovered many examples of non-Mendelian inheritance, to the point that one cannot deduce any law which says “If an organism has traits X, Y, Z then it will follow Mendelian genetics.” Instead, one can only say that “an organism is Mendelian if we examine it and it happens to be actually Mendelian.”
One might bring up natural selection as an example of a law in biology. However, as Josh and other biologists have repeatedly emphasized, natural selection is far from being the only dominant force in evolution. Secondly, in domains where it holds, natural selection seems to not really be a distinctly biological law but merely a tautological mathematical statement with little actual content: organisms which are more fit will reproduce more.
Note that this is deeper than merely a naive statement that “biology is more complex than physics, so it’s hard to find generalizable laws” - instead, it’s a statement that you shouldn’t expect biology to have any universal applicability, since the processes that produce life are contingent in the first place.