146 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 2 



It is commonly objected that our uncertainty as to what the 

 electron will do in the future is due not to indeterminism but to 

 ignorance. It is asserted that some character exists in the electron 

 or its surroundings which decides its future, only physicists have 

 not 3'et learned how to detect it. You will see later how I deal with 

 this suggestion. But I would here point out that if the physicist is 

 to take'^any part in the wider discussion on determinism as affecting 

 the significance of our lives and the responsibility of our decisions, 

 he must do so on the basis of what he has discovered, not on the 

 basis of what it is conjectured he might discover. His first step 

 should be to make clear that he no longer holds the position, occupied 

 for so long, of chief advocate for determinism, and that if there is any 

 deterministic law in the physical universe he is unaware of it. He 

 steps aside and leaves it to others— philosophers, psychologists, the- 

 ologians—to come forward and show, if they can, that they have 

 found indications of determinism in some other way.'^ If no one 

 comes forward the hypothesis of determinism presumably drops; 

 and the question whether physics is actually antagonistic to it scarcely 

 arises. It is no use looking for an opposer until there is a proposer 

 in the field. 



INFERENTIAL KNOWLEDGE 



It is now necessary to examine rather closely the nature of our 

 knowledge of the physical universe. , 



All our knowledge of physical objects is by inference. Our minds 

 have no means of getting into direct contact with them ; but the objects 

 emit and scatter light waves, and they are the source of pressures 

 transmitted through adjacent material. They are like broadcasting 

 stations that send out signals which we can receive. At one stage 

 of the transmission the signals pass along nerves withm our bodies. 

 Ultimately visual, tactual, and other sensations are provoked m the 

 mind It is from these remote effects that we have to argue back 

 to the properties of the physical object at the far end of the chain 

 of transmission. The image which arises in the mmd is not the 

 physical object, though it is a source of information about the 

 physical object; to confuse the mental object with the physical 

 object is to confuse the clue with the criminal. Life would be 

 impossible if there were no kind of correspondence between the 

 external world and the picture of it in our minds; and natural 

 selection (reinforced where necessary by the selective activity of the 



^ With a view to learning what might be said from the philosophical side agains^t the 

 abandonment of detorminis;;, I took part in a symposium of the ^^^^^^f^.f "^^^^^ 

 Mind Association in July. 1931. ludetorminists wore strongly represented^ but vuif u 

 nately there were no determinists in the symposium, and apparently none in the audi* nee 

 which discussed it. I can scarcely suppose that determinist philosophers are extnict. but 

 it may be left to their colleagues to deal with them. 



