Now this is true not only of quite empty terms but of terms that carry a meaning.  It is a mental necessity that we should make classes and use general terms, and as soon as we do that we fall into immediate danger of unjustifiably increasing the intension of these terms.  You will find a large proportion of human prejudice and misunderstanding arises from this universal proclivity.

1.7.  Negative terms.

There is a particular sort of empty terms that has been and is conspicuously dangerous to the thinker, the class of negative terms.  The negative term is in plain fact just nothing; “Not-A” is the absence of any trace of the quality that constitutes A, it is the rest of everything for ever.  But there seems to be a real bias in the mind towards regarding “Not-A” as a thing mysteriously in the nature of A, as though “Not-A” and A were species of the same genus.  When one speaks of Not-pink one is apt to think of green things and yellow things and to ignore anger or abstract nouns or the sound of thunder.  And logicians, following the normal bias of the mind, do actually present A and not-A in this sort of diagram:—­

(the letter A inside a circular boundary, together with the words Not A, all inside a bigger circular boundary.)

ignoring altogether the difficult case of the space in which these words are printed.  Obviously the diagram that comes nearer experienced fact is:—­

(the word Not, followed by the letter A inside a circular boundary, followed by the letter A)

with no outer boundary.  But the logician finds it necessary for his processes to present that outer Not-A as bounded (Vide e.g.  Kayne’s “Formal Logic” re Euler’s diagrams and Immediate Inferences.), and to speak of the total area of A and Not-A as the Universe of Discourse; and the metaphysician and the commonsense thinker alike fall far too readily into the belief that this convention of method is an adequate representation of fact.

Let me try and express how in my mind this matter of negative terms has shaped itself.  I think of something which I may perhaps best describe as being off the stage or out of court, or as the Void without Implications, or as Nothingness, or as Outer Darkness.  This is a sort of hypothetical Beyond to the visible world of human thought, and thither I think all negative terms reach at last, and merge and become nothing.  Whatever positive class you make, whatever boundary you draw, straight away from that boundary begins the corresponding negative class and passes into the illimitable horizon of nothingness.  You talk of pink things, you ignore, as the arbitrary postulates of Logic direct, the more elusive shades of pink, and draw your line.  Beyond is the not-pink, known and knowable, and still in the not-pink region one comes to the Outer Darkness.  Not blue, not happy, not iron, all the not classes meet in that Outer Darkness.  That same Outer Darkness