Explanation of the word "theory" in the field of sciences


Evolution Picture

Some reject the Darwinism by saying that it is "only a theory". This argument has two weaknesses. Firstly, it ignores the fact that Darwin affirmed two things: that the modern species go down from ancestral forms and that the natural selection is the principal mechanism of the evolution. The evolution is attested by historical facts. To take no account of the data showing that the Mammals go down from the Reptiles simply because nobody could observe the transition is equivalent to denying the French Revolution under pretexte that none among us was witness of it.

Then, what remains theoretical about the evolution? The theories remain attempts of explanation, synthesis and integration of the facts. For the biologists, the theory of evolution of Darwin bring back to the natural selection, the mechanism that Darwin put in to explain the facts revealed by paleontology, biogeography and the other historical disciplines.

Consequently, the argument "only a theory" relates only to the second assertion of Darwin, the theory of the natural selection. But here appears the second weakness of the matter. The theory term does not have in the scientific field the same significance as in the current language. In its familiar employment, the theory term has the significance that the scientists give to the word hypothesis. In sciences, a theory constitutes a statement more global than an hypothesis. A theory, like the theory of the gravitation of Newton or that of the natural selection of Darwin, gives an account of multiple facts and tries to explain a large variety of phenomena. And a theorie is recognized in sciences only if the theory is resisting repeated systematic checks in the form of experiments and observations. Moreover, the good scientists do not let the theories set up in dogmas. For example, of many biologists of evolution wonder today if only the natural selection suffices to explain the history told by the geological files. The study of evolution becomes more vigorous and more dynamics than ever. But the fact of wondering about the mechanism of the evolution does not imply to considere the evolution like "simple theory". We can compare the debate on the theory of the evolution with the debate on the theories of the gravitation: the objects fall and us, we discuss the causes of their fall.

Evolution Picture
Darvin has gave to biology a solid scientific base by allotting the diversity of the living to natural causes than to a supernatural intention. Despite everything, the variety and the harmony of the products of the evolution do not cease to fill us with wonder and to inspire us. As Darwin wrote in the last paragraph of the Origin of the species: "Is there not a true grandeur in this manner of considering the life?"