So my world of fact shaped itself. I find it altogether impossible to question or doubt that world of fact. Particular facts one may question as facts. For instance, I think I see an unseasonable yellow wallflower from my windows, but you may dispute that and show that it is only a broken end of iris leaf accidentally lit to yellow. That is merely a substitution of fact for fact. One may doubt whether one is perceiving or remembering or telling facts clearly, but the persuasion that there are facts, independent of one’s interpretations and obdurate to one’s will, remains invincible.
1.4. SCEPTICISM OF THE INSTRUMENT.
At first I took the world of fact as being exactly as I perceived it. I believed my eyes. Seeing was believing, I thought. Still more did I believe my reasoning. It was only slowly that I began to suspect that the world of fact could be anything different from the clear picture it made upon my mind.
I realised the inadequacy of the senses first. Into that I will not enter here. Any proper text book of physiology or psychology will supply a number of instances of the habitual deceptions of sight and touch and hearing. I came upon these things in my reading, in the laboratory, with microscope or telescope, lived with them as constant difficulties. I will only instance one trifling case of visual deception in order to lead to my next question. One draws two lines strictly parallel; so
(two horizontal and parallel lines.)
Oblique to them one draws a series of lines; so
(a series of parallel and closely-spaced lines drawn through each horizontal line, one series (top) sloping to the right, the other (bottom) to the left)
and instantly the parallelism 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 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 infinitesimal degree from the previous average properties of the species. There is no property of any species, even the properties that constitute the specific definition, that is not a matter of more or less.
If, for example, as species be distinguished by a single large red spot on the back, you will find if you go over a great number of specimens that red spot shrinking