14 THE PRESIDENTIAL ADDRESS 
Even the inadequate particle-picture told us something very 
similar in its own roundabout stammering way. At first it seemed 
to be telling us of a nature distinct from our minds, which moved 
as directed by throws of the dice, and then it transpired that the dice 
were thrown by our own minds. Our minds enter into both pic- 
tures, although in somewhat different capacities. In the particle- 
picture the mind merely decides under what conventions the map 
is to be drawn ; in the wave-picture it perceives and observes and 
draws the map. We should notice, however, that the mind enters 
both pictures only in its capacity as a receptacle—never as an 
emitter. 
The determinism which appears in the new physics is one of 
waves, and so, in the last resort, of knowledge. Where we are not 
ourselves concerned, we can say that event follows event ; where 
we are concerned, only that knowledge follows knowledge. And 
even this knowledge is one only of probabilities and not of cer- 
tainties ; it is at best a smeared picture of the clear-cut reality which 
we believe to lie beneath. And just because of this, it is impossible 
to decide whether the determinism of the wave-picture originates 
in the underlying reality or not—Can our minds change what is 
happening in reality, or can they only make it look different to us by 
changing our angle of vision? We do not know, and as I do not 
see how we can ever find out, my own opinion is that the problem of 
free-will will continue to provide material for fruitless discussion 
until the end of eternity. 
The contribution of the new physics to this problem is not that 
it has given a decision on a long-debated question, but that it has 
reopened a door which the old physics had seemed to slam and bolt. 
We have an intuitive belief that we can choose our lunch from the 
menu or abstain from housebreaking or murder; and that by our 
own volition we can develop our freedom to choose. We may, of 
course, be wrong. ‘The old physics seemed to tell us that we were, 
and that our imagined freedom was all an illusion ; the new physics 
tells us it may not be. 
The old physics showed us a universe which looked more like a 
prison than a dwelling-place. ‘The new physics shows us a building 
which is certainly more spacious, although its interior doors may be 
either open or locked—we cannot say. But we begin to suspect it 
may give us room for such freedom as we have always believed we 
possessed ; it seems possible at least that in it we can mould events 
to our desire, and live lives of emotion, intellect, and endeavour. 
It looks as though it might form a suitable dwelling-place for man, 
and not a mere shelter for brutes. 
The new physics obviously carries many philosophical implica- 
tions, but these are not easy to describe in words. They cannot be. 
