his writings - did fulfil what Heisenberg rightly feels to have been
his true task.2

We mentioned Heisenberg's speech as a symptom of a certain tendency,
characteristic of the latest phase in science, to survey critically its
own epistemological foundations. A few years previous to Heisenberg's
speech, the need of such a survey found an eloquent advocate in the
late Professor A. N. Whitehead, in his book Science and the Modern
World, where, in view of the contradictory nature of modern physical
theories, he insists that 'if science is not to degenerate into a
medley of ad hoc hypotheses, it must become philosophical and enter
upon a thorough criticism of its own foundations'.

Among the scientists who have felt this need, and who have taken pains
to fulfil it, the late Professor A. Eddington obtains an eminent
position. Among his relevant utterances we will quote here the
following, because it contains a concrete statement concerning the
field of external observation which forms the basis for the modern
scientific world-picture. In his Philosophy of Physical Science we find
him stating that 'ideally, all our knowledge of the universe could have
been reached by visual sensation alone - in fact by the simplest form
of visual sensation, colourless and non-stereoscopic'.3 In other words,
in order to obtain scientific cognition of the physical world, man has
felt constrained to surrender the use of all his senses except the
sense of sight, and to limit even the act of seeing to the use of a
single, colour-blind eye.

Let us listen to yet another voice from the ranks of present-day
science, expressing a criticism which is symptomatic of our time. It
comes from the late physiologist, Professor A, Carrel, who, concerning