and methods remote and
secluded from the world of fact in which I lived and with which I had to
deal. As it came to me in the ordinary textbooks, it presented itself
as the science of inference using the syllogism as its principal
instrument. Now I was first struck by the fact that while my teachers in
Logic seemed to be assuring me I always thought in this form:--

"M is P,
S is M,
S is P,"

the method of my reasoning was almost always in this form:--

"S1 is more or less P,
S2 is very similar to S1,
S2 is very probably but not certainly more or less P.
Let us go on that assumption and see how it works."

That is to say, I was constantly reasoning by analogy and applying
verification. So far from using the syllogistic form confidently, I
habitually distrusted it as anything more than a test of consistency
in statement. But I found the textbooks of logic disposed to ignore my
customary method of reasoning altogether or to recognise it only where
S1 and S2 could be lumped together under a common name. Then they put it
something after this form as Induction:--

"S1, S2, S3, and S4 are P
S1 + S2 + S3 + S4 +... are all S
All S is P."

I looked into the laws of thought and into the postulates upon which the
syllogistic logic is based, and it slowly became clear to me that from
my point of view, the point of view of one who seeks truth and reality,
logic assumed a belief in the objective reality of classification of
which my studies in biology and mineralogy had largely disabused me.
Logic, it seemed to me, had taken a common innate error of the mind and
had emphasised it in order to develop a system of reasoning that should
be exact in its processes. I turned my attention to the examination
of that. For in common with the general run of men I had supposed that
logic professed to supply a trustworthy science and method for the
investigation and expression of reality.

A mind nourished on anatomical study is of course permeated with the
suggestion of the vagueness and instability of biological species.
A biological species is quite obviously a great number of unique
individuals which is separable from other biological species only by
the fact that an enormous number of other linking individuals are
inaccessible in time--are in other words dead and gone--and each
new individual in that species does, in the distinction of its own
individuality, break away in however infi