Before I can think you to mean my world, you must affect my world; before I can think you to mean much of it, you must affect much of it; and before I can be sure you mean it as I do, you must affect it just as I should if I were in your place.  Then I, your critic, will gladly believe that we are thinking, not only of the same reality, but that we are thinking it alike, and thinking of much of its extent.

Without the practical effects of our neighbor’s feelings on our own world, we should never suspect the existence of our neighbor’s feelings at all, and of course should never find ourselves playing the critic as we do in this article.  The constitution of nature is very peculiar.  In the world of each of us are certain objects called human bodies, which move about and act on all the other objects there, and the occasions of their action are in the main what the occasions of our action would be, were they our bodies.  They use words and gestures, which, if we used them, would have thoughts behind them,—­no mere thoughts uberhaupt, however, but strictly determinate thoughts.  I think you have the notion of fire in general, because I see you act towards this fire in my room just as I act towards it,—­poke it and present your person towards it, and so forth.  But that binds me to believe that if you feel ‘fire’ at all, this is the fire you feel.  As a matter of fact, whenever we constitute ourselves into psychological critics, it is not by dint of discovering which reality a feeling ‘resembles’ that we find out which reality it means.  We become first aware of which one it means, and then we suppose that to be the one it resembles.  We see each other looking at the same objects, pointing to them and turning them over in various ways, and thereupon we hope and trust that all of our several feelings resemble the reality and each other.  But this is a thing of which we are never theoretically sure.  Still, it would practically be a case of grubelsucht, if a ruffian were assaulting and drubbing my body, to spend much time in subtle speculation either as to whether his vision of my body resembled mine, or as to whether the body he really meant to insult were not some body in his mind’s eye, altogether other from my own.  The practical point of view brushes such metaphysical cobwebs away.  If what he have in mind be not my body, why call we it a body at all?  His mind is inferred by me as a term, to whose existence we trace the things that happen.  The inference is quite void if the term, once inferred, be separated from its connection with the body that made me infer it, and connected with another that is not mine at all.  No matter for the metaphysical puzzle of how our two minds, the ruffian’s and mine, can mean the same body.  Men who see each other’s bodies sharing the same space, treading the same earth, splashing the same water, making the same air resonant, and pursuing the same game and eating out of the same dish, will never practically believe in a pluralism of solipsistic worlds.