10 REPORT—1904. 
The difficulty only arises when experience apparently says one thing 
and scientific instinct persists in saying another. Two such cases I have 
already mentioned ; others will easily be found by those who care to seek. 
What is the origin of this instinct, and what its value ; whether it be a 
mere prejudice to be brushed aside, or a clue which no wise man would 
disdain to follow, I cannot now discuss. For other questions there are, 
not new, yet raised in an acute form by these most modern views of 
matter, on which I would ask your indulgent attention for yet a few 
moments, 
1B 
That these new views diverge violently from those suggested by 
ordinary observation is plain enough. No scientific education is likely 
to make us, in our unreflective moments, regard the solid earth on 
which we stand, or the organised bodies with which our terrestrial fate is 
so intimately bound up, as consisting wholly of electric monads very 
sparsely scattered through the spaces which these fragments of matter 
are, by a violent metaphor, described as ‘occupying.’ Not less plain is it 
that an almost equal divergence is to be found between these new theories 
and that modification of the common-sense view of matter with which 
science has in the main been content to work. 
What was this modification of common sense? It is roughly indicated 
by an old philosophic distinction drawn between what were called the 
‘primary ’ and the ‘ secondary’ qualities of matter. The primary quali- 
ties, such as shape and mass, were supposed to possess an existence quite 
independent of the observer ; and so far the theory agreed with common 
sense. The secondary qualities, on the other hand, such as warmth and 
colour, were thought to have no such independent existence, being, 
indeed, no more than the resultants due to the action of the primary 
qualities on our organs of sense-perception ; and here, no doubt, common 
sense and theory parted company. 
You need not fear that I am going to drag you into the controversies 
with which this theory is historically connected. They have left abiding 
traces on more than one system of philosophy, They are not yet solved. 
In the course of them the very possibility of an independent physical 
universe has seemed to melt away under the solvent powers of critical 
analysis. But with all this I am not now concerned. I do not propose 
to ask what proof we have that an external world exists, or how, if it 
does exist, we are able to obtain cognisance of it. These may be ques- 
tions very proper to be asked by philosophy ; but they are not proper 
questions to be asked by science. For, logically, they are antecedent to 
physical science, and we must reject the sceptical answers to both of them 
before any such science becomes possible at all. My present purpose requires 
me to do no more than observe that, be this theory of the primary and 
secondary qualities of matter good or bad, it is the one on which, as a 
matter of fact, science has in the main proceeded, It was with matter thus 
