424 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



determined by a number of factors which I call motives, 

 reasons, desires, past experiences, etc.; in fact I insist that 

 my volition is precisely the outcome of the survey of just 

 such factors. But this examination of motives, reasons, etc., 

 is nothing other than the act of making the decision. My 

 decision is not independent of these factors ; it is these factors 

 themselves blended into a harmonious whole. Hence when 

 I say that my decision has been determined by a previous 

 mind-state, all that I am asserting is that I myself have 

 determined the decision, for by my self at any moment I 

 mean simply the mind-state at that moment, which includes, 

 of course, the effects of all previous mind-states. But to 

 act according to the dictates of my self is not to be deter- 

 mined but to be free. Self-determinism is freedom. 



Apparently, therefore, the differences between the phys- 

 ical and the psycho-physical analyses of the act of behavior 

 are two in number : (a) The latter theory permits a physical 

 state to be caused by something which is non-physical, i.e., 

 by a mind-state, (b) The latter theory permits a mind- 

 state to be caused only by something which is non-physical, 

 i.e., another mind-state. The former theory permits neither 

 of these to be true. Both theories are causal, for they 

 both insist that the eventual movement is the outcome of 

 previous events. In fact both theories claim that the move- 

 ment is the immediate outcome of an event in a brain. The 

 difference arises when the analysis is pushed back further. 

 What is to be done with this brain-state which is the imme- 

 diate cause of the actP Is it caused by a previous brain-state, 

 and only by such? If so, the act of the individual is part of a 

 physical causal chain and is determined. Is the brain-state 

 caused by a previous mind-state, and only by such? If so, the 

 individual is part of a causal chain which is not wholly physi- 

 cal in character, and this is partly what is meant by saying 

 that the individual is free. He is free in the sense that his 

 behavior follows from his decisions. In this sense the indi- 

 vidual is free to act as he wills. But is he free to will as he 

 wills, i.e., is the individual's volition itself an event in a causal 



