The Grammar of Science book – which was anti-materialist – influenced Einstein’s theories of relativity, and was the first book that Einstein and his colleagues read after forming a reading group when he was 23 (see the wikipedia entry).
Pearson was a socialist, apparently a feminist, refused knighthood, and was an outrageous eugenicist and, if one reads between the lines, racist, clearly mistaking martial superiority for moral superiority.
From wikipedia: ”History shows me one way, and one way only, in which a high state of civilization has been produced, namely, the struggle of race with race, and the survival of the physically and mentally fitter race. If you want to know whether the lower races of man can evolve a higher type, I fear the only course is to leave them to fight it out among themselves, and even then the struggle for existence between individual and individual, between tribe and tribe, may not be supported by that physical selection due to a particular climate on which probably so much of the Aryan’s success depended . . .” (Karl Pearson, National Life from the Standpoint of Science [London, 1905])
From the (all too hopeful) preface to the 1900 2nd Edition:
“There are many signs that a sound idealism is surely replacing, as a basis for natural philosophy, the crude materialism of the older physicists. More than one professor of metaphysics has actually discovered that he can best attack modern science by criticising ancient statements as to mechanism from a standpoint remarkably similar to that of the Grammar.
Step by step men of science are coming to recognize that mechanism is not at the bottom of phenomena, but is only the conceptual shorthand by aid of which they can briefly describe and resume phenomena. That all science is description and not explanation, that the mystery of change in the inorganic world is just as great and just as omnipresent as in the organic world, are statements which will appear platitudes to the next generation.
Formerly men had belief as to the super-sensuous, and thought they had knowledge of the sensuous. The science of the future, while agnostic as to the supersensuous, will replace knowledge by belief in the perceptual sphere, and reserve the term knowledge for the conceptual sphere – the region of their own concepts and ideas – of ether, atom, organic corpuscle, and vital force – of physical and plasma mechanics.
That this change of view as to the basis of science cannot take place without misunderstanding, or without giving an opportunity to those who dislike science to decry its weaknesses, is only natural. To change the basis of operations during a campaign always gives a chance to the enemy, but the chance must be risked if thereby we place ourselves permanently in a position of greater strength for offence and defence. If the reader questions whether there is still war between science and dogma, I must reply that there always will be as long as knowledge is opposed to ignorance. To know requires exertion, and it is intellectually easiest to shirk effort altogether by accepting phrases which cloak the unknown in the undefinable.”