John Tyndall, the rhetorician of molecularity. Part two. Questions put to nature

Abstract

Following the discussion in Part One of this paper, an attempt is made here to understand the way in which Tyndall justified his bold claim that the introduction of molecular explanans in science necessitated an act of the imagination. Being conscious of the prospective emergence of a new scientific field out of the extensive dialogue of scientists over the conditions of material molecularity, and having the ambition to place his own research on absorption and radiation at the centre of the relevant developments, Tyndall was prepared to couple his imaginative suggestions with meticulous experimentation. With his unparalleled ability to master all the minute details of the experimental procedures he was following, Tyndall not only realized the significance of what he thought to be a basic constituent of scientific ethics, but could also design and perform the crucial experiments that enabled him to take a closer look at the submicroscopic level of physical reality. In so doing, he attempted to go far beyond the minimal expectations of 19th-century molecular discourse, insofar as he claimed to have given not only a proof of the molecular underpinnings of physical phenomena but also a definite picture of the individual molecule itself.