Probability and Design 277 



prospective reference to those of retrospect is evidently 

 the formula for probabilities. I do not see how that for- 

 mula can escape being considered a category of retrospect, 

 applied to material which does not admit of any narrower 

 or more special retrospective formulation. 



Now the inference from this is that our predicate ' real- 

 ity,' in certain cases, is not adequately expressed in terms 

 of the experienced behaviour of so-called real content. 

 The very experience on the basis of which we are wont to 

 predicate reality testifies to its own inadequacy. There is 

 no way to avoid the alternatives that either the notion of 

 reality does not rest upon experiences of behaviour, or that 

 the problematic judgments based upon those experiences 

 of progressive organization which we know currently 

 under the term ' development,' are as fundamental to these 

 kinds of reality as are those more static judgments based 

 on history or origin. 



5. Probability and Design 



It may be well, in view of the importance of this con- 

 clusion, to see something more of its bearings in philos- 

 ophy. The historical theories of 'design,' or teleology in 

 nature, have involved this question. And those familiar 

 with the details of the design arguments pro and con will 

 not need to have brought to mind the confusion which has 

 arisen from the mixing up of the 'prospective' and 'retro- 

 spective ' points of view. Design, to the mind of many of 

 the older theistic writers, was based upon relative unpre- 

 dictability or better, infinite improbability. Such an 

 argument looks forward ; it is reasoning in the category of 

 organization, and under the ' prospective ' reference. The 

 organization called mental must be appealed to. What, 



