‘THE STABILITY OF TRUTH. 361 
and at the same time the personal equation or individual 
source of error is largely eliminated. The use of instru- 
ments of precision is the special charac- 
teristic of the advance of science. No 
instrument of precision can give us the 
ultimate essence of any part of the universe. No scien- 
tific experiment can do away with the measure of human 
experience as the basis of intelligibility. At the same 
time we can throw large illuminations into “the dimly 
lighted room” in which, according to Balfour, the phe- 
nomena of consciousness takes place. By the simple 
process of photography, for example, we may reproduce 
the objects of our environment. That such pictures do 
express phases of reality admits of no doubt; for in the 
photographic camera, all personal equation is eliminated. 
As to form of outline and reflection of light, “the sun 
paints true,” and the paintings thus made by means of 
the action of non-living matter produce on our senses 
impressions coinciding with those of the outside world 
itself. 
How do we know that this is truth? Because belief 
in it adds to the safety of life; we can trust our lives to 
it. If it were an illusion it would kill, 
Trust in reality because action based on illusion leads to 
makes life safe. 
death. 
One can trust his life, for example, to the message 
sent on a telegraph wire. All who travel by rail do this 
daily. One can trust his life to the reading of a ther- 
mometer. The chemist’s tests will select for us foods 
among poisons. We may trust these tests absolutely. 
We may safely and sometimes wisely take poisons into 
our bodies if we know what we are doing. By the ad- 
vice of a physician, trusting in the weigher’s instrument 
of precision, poisons may do no harm. One grain of 
strychnine may be an aid to vital processes; a dozen 
Hyperesthesia 
of science. 
