A Logical Calculus of the Ideas Immanent in Nervous Activity 397 



observations and of these to the facts is all too clear, for it is ap- 

 parent that every idea and every sensation is realized by activity 

 within that net, and by no such activity are the actual afferents 

 fully determined. 



There is no theory we may hold and no observation we can make 

 that will retain so much as its old defective reference to the facts 

 if the net be altered. Tinnitus, paraesthesias, hallucinations, de- 

 lusions, confusions and disorientations intervene. Thus empiry 

 confirms that if our nets are undefined, our facts are undefined, 

 and to the "real'' we can attribute not so much as one quality 

 or "form." With determination of the net, the unknowable object 

 of knowledge, the "thing in itself,'' ceases to be unknowable. 



To psychology, however defined, specification of the net would 

 contribute all that could be achieved in that field — even if the 

 analysis were pushed to ultimate psychic units or "psychons," for 

 a psychon can be no less than the activity of a single neuron. 

 Since that activity is inherently propositional. all psychic events 

 have an intentional, or "semiotic," character. The "all-or-none" 

 law of these activities, and the conformity of their relations to 

 those of the logic of propositions, insure that the relations of 



-^ EXPRESSION FOR THE FIGURES 



In the figure the neuron cv is always marked with the numeral i upon the 

 body of the cell, and the corresponding action is denoted by W with i as sub- 

 script, as in the text. 



Figure la N-i(t) . = . A^i(/ - 1) 



Figure lb A^3(0 • = • A^i^' - 1) V N2(t - 1) 



Figure Ic A^3(0 . = . A^i(/ - D • NM - 1) 



Figure Id Nsit) . = . N,(t - 1) . ^ N-2(t - 1) 



Figure le .V,(0 : = : .V,(/ - 1) . V . ,V2(/ - 3) . - A^,(/ - 2) 



N,(t) . = . N-At - 2) . N-zit - 1) 



Figure If N^{t) : = : ~ A^i(; - 1) . N ■i{t - \)vN^{t - 1) . V . yVi(t - 1) • 



N-At - 1) . iVsO - 1) 

 is!, it) : = : - 7Vi(< - 2) . N At - 2) v N -M - 2) . v . NAt - 2) . 



NAt - 2) . ^At - 2) 

 Figure Ig A^3(0 . = . NAt - 2) . ~ iV,(< - 3) 

 Figure Ih iVsCO . = . A^,(/ - 1) . NAt - 2) 

 Figure li .V3(0 : = : Ar,(/ - 1) . V . ,V,(^ - 1) . {Ex)t - 1 . A^,(.v) . N Ax) 



