516 Scientific Proceedings, Royal Dublin Society. 



object which is an object of reflection, not of sense). It is not 

 essential to adopt any noumenal hypothesis, so far as the purposes 

 of this essay are concerned, and none such is involved in anything 

 that is said in the preceding pages. But it will give definiteness 

 to our thoughts to have provisionally before our minds a noumenal 

 hypothesis which is probably true ; and it is of use to dispel errors 

 which are apt tacitly to creep into our ways of thinking, from the 

 circumstance that we and all men have had instilled into us in our 

 childhood the noumenal hypothesis that material substances and 

 forces exist, and even that they occupy positions in space the same 

 as or close to those which seem to be occupied by human percej)- 

 tions. All this is embodied, too, in the ordinary forms of speech 

 which everyone has daily to use ; and under these circumstances 

 men, for the most part, unhesitatingly believe this crude noumenal 

 hypothesis to be the true theory of that part of the universe which 

 acts on us through our senses. It is manifest that this is a some- 

 what gross error (see § 9, p. 479) ; but even careful thinkers are 

 entrapped into mistakes by it in consequence of the forms of 

 speech they are forced to employ. 



We have found that in one very remarkable instance l the autic 

 antitheta of certain motions in Nature are thoughts — that if a by- 

 stander were armed with adequate appliances for ascertaining what 

 is going on in my brain while I am thinking, then what I should 

 experience to be thought is the remote cause with several interme- 

 diate causes of a complex effect within his mind which he would 

 call observing motions in my brain. 



Perhaps it is better to endeavour to consider the causal rela- 

 tions of my thoughts apart from the thoughts themselves, and to 

 describe the process more in detail as follows. My thoughts stand 

 in certain causal relations to one another, to parts of the synergos, 



1 Every change in Nature may, from the diacrinomenal standpoint, be described as 

 motion ; and that motion of the brain, which is the protheton of human thought, is part 

 of the change which is going on in the brain while we are awake, and which does not 

 go on when we fall asleep. 



So also in regard to particular thoughts. So long as " I am looking at the door" 

 some change is taking place in my brain, which is, or a part of which is, the protheton 

 of the perception that I then have. The perception is what really exists ; the change 

 in the brain has only an objective existence (§ 12, p. 480) ; and these two are related to 

 one another as antitheton and protheton. See Diagram III., p. 486. 



In this case the antitheta of some motions going on in the brain are thoughts. 

 Are the antitheta of all the other motions thoughts ? 



