ence, through a year of dissection and some weeks at the astronomical
telescope. So I built up my conceptions of a real world out of facts
observed and out of inferences of a nature akin to fact, of a world
immense and enduring, receding interminably into space and time. In that
I found myself placed, a creature relatively infinitesimal, needing and
struggling. It was clear to me, by a hundred considerations, that I in
my body upon this planet Earth, was the outcome of countless generations
of conflict and begetting, the creature of natural selection, the heir
of good and bad engendered in that struggle.

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