10 THE PRESIDENTIAL ADDRESS 
If we ask the new physics to specify an electron for us, it does not 
give us a mathematical specification of an objective electron, but 
rather retorts with the question : ‘How much do you know about 
the electron in question?’ We state all we know, and then comes 
the surprising reply, ‘ That is the electron.’ The electron exists 
only in our minds—what exists beyond, and where, to put the idea 
of an electron into our minds we do not know. ‘The new physics 
can provide us with wave-pictures depicting electrons about which 
we have varying amounts of knowledge, ranging from nothing at all 
to the maximum we can know with the blunt probes at our command, 
but the electron which exists apart from our study of it is quite 
beyond its purview. 
Let me try and put this in another way. The old physics im- 
agined it was studying an objective nature which had its own exist- 
ence independently of the mind which perceived it—which, indeed, 
had existed from all eternity whether it was perceived or not. It 
would have gone on imagining this to this day, had the electron 
observed by the physicists behaved as on this supposition it ought 
to have done. 
But it did not so behave, and this led to the birth of the new physics, 
with its general thesis that the nature we study does not consist so 
much of something we perceive as of our perceptions ; it is not the 
object of the subject-object relation, but the relation itself. There 
is, in fact, no clear-cut division between the subject and object ; 
they form an indivisible whole which now becomes nature. This 
thesis finds its final expression in the wave-parable, which tells us 
that nature consists of waves and that these are of the general 
quality of waves of knowledge, or of absence of knowledge, in our 
own minds. 
Let me digress to remind you that if ever we are to know the true 
nature of waves, these waves must consist of something we already 
have in our own minds. Now knowledge and absence of knowledge 
satisfy this criterion as few other things could ; waves in an ether, 
for instance, emphatically did not. It may seem strange, and almost 
too good to be true, that nature should in the last resort consist of 
something we can really understand ; but there is always the simple 
solution available that the external world is ee of the same 
nature as mental ideas. 
At best this may seem very academic and up in the air—at the 
worst it may seem stupid and even obvious. I agree that it would 
be so, were it not for the one outstanding fact that observation 
supports the wave-picture of the new physics whole-heartedly and 
without hesitation. Whenever the particle-picture and the wave- 
picture have come into conflict, observation has discredited the 
particle-picture and supported the wave-picture—not merely, be it 
