First and Last Things | Page 8

seems to be disturbed. If the second figure is presented to
any one without sufficient science to understand this delusion, the impression is created
that these lines converge to the right and diverge to the left. The vision is deceived in its
mental factor and judges wrongly of the thing seen.
In this case we are able to measure the distance of the lines, to find how the main lines
looked before the cross ones were drawn, to bring the deception up against fact of a
different sort and so correct the mistake. If the ignorant observer were unable to do that,
he might remain permanently under the impression that the main lines were out of
parallelism. And all the infirmities of eye and ear, touch and taste, are discovered and
checked by the fact that the erroneous impressions presently strike against fact and
discover an incompatibility with it. If they did not we should never have discovered them.
If on the other hand they are so incompatible with fact as to endanger the lives of the
beings labouring under such infirmities, they would tend to be eliminated from among
our defects.
The presumption to which biological science brings one is that the senses and mind will
work as well as the survival of the species may require, but that they will not work so
very much better. There is no ground in matter-of-fact experience for assuming that there
is any more inevitable certitude about purely intellectual operations than there is about
sensory perceptions. The mind of a man may be primarily only a food-seeking,
danger-avoiding, mate-finding instrument, just as the mind of a dog is, just as the nose of
a dog is, or the snout of a pig.
You see the strong preparatory reason there is in this view of life for entertaining the
suppositions that:--
The senses seem surer than they are.
The thinking mind seems clearer than it is and is more positive than it ought to be.
The world of fact is not what it appears to be.
1.5. THE CLASSIFICATORY ASSUMPTION.
After I had studied science and particularly biological science for some years, I became a
teacher in a school for boys. I found it necessary to supplement my untutored conception

of teaching method by a more systematic knowledge of its principles and methods, and I
took the courses for the diplomas of Licentiate and Fellow of the London College of
Preceptors which happened to be convenient for me. These courses included some of the
more elementary aspects of psychology and logic and set me thinking and reading further.
From the first, Logic as it was presented to me impressed me as a system of ideas 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