The Phylogenetic Distribution of Electroreception: Evidence for Convergent Evolution of a Primitive Vertebrate Sense Modality

Abstract

Source: The Facts of Perception (1878) from Selected Writings of Hermann Helmholtz, Wesleyan University Press. The Whole speech, barring inrtoductory paragraphs and appendices are repoduced here. The problems which that earlier period considered fundamental to all science were those of the theory of knowledge: What is true in our sense perceptions and thought? and In what way do our ideas correspond to reality? Philosophy and the natural sciences attack these questions from opposite directions, but they are the common problems of both. Philosophy, which is concerned with the mental aspect, endeavours to separate out whatever in our knowledge and ideas is due to the effects of the material world, in order to determine the nature of pure mental activity. The natural sciences, on the other hand, seek to separate out definitions, systems of symbols, patterns of representation, and hypotheses, in order to study the remainder, which pertains to the world of reality whose laws they seek, in a pure form. Both try to achieve the same separation, though each is interested in a different part of the divided field. The natural scientist no more than the philosopher can ignore epistemological questions when he is dealing with sense perception or when he is concerned with the fundamental principles of geometry, mechanics, or physics. Since my work has entered many times into both the region of science and the region of philosophy, I should like to attempt to survey what has been done from the side of the natural sciences to answer the questions which have just been stated. The laws of thought, after all, are the same for the scientist as for the philosopher. In all cases where the facts of daily experience, which are already very copious, afford a clear-sighted thinker with a disinterested sense of the truth sufficient information for making correct judgments, the scientist must be satisfied to recognise that a methodologically complete collection of the facts of experience will simply confirm those judgments, though there are occasionally, of course, some conflicting cases. This is my excuse (if it must be excused) for the fact that in general, in the following paper, no completely new answers -on the contrary, only rather old answers, long since given to the questions to be dealt with -will be presented to you. Often enough, of course, even old concepts gain new illumination and new meaning from newly ascertained facts.