The Definition of Reality. It is time we came to grips with the loose terms Reality and Existence, which we have been using without any inquiry into what they are meant to convey. I am afraid of this word Reality, not connoting an ordinarily definable characteristic of the things it is applied to but used as though it were some kind of celestial halo. I very much doubt if any one of us has the faintest idea of what is meant by the reality or existence of anything but our own Egos. That is a bold statement, which I must guard against misinterpretation. It is, of course, possible to obtain consistent use of the word “reality” by adopting a conventional definition. My own [Pg 283] practice would probably be covered by the definition that a thing may be said to be real if it is the goal of a type of inquiry to which I personally attach importance. But if I insist on no more than this I am whittling down the significance that is generally assumed. In physics we can give a cold scientific definition of reality which is free from all sentimental mystification. But this is not quite fair play, because the word “reality” is generally used with the intention of evoking sentiment. It is a grand word for a peroration. “The right honourable speaker went on to declare that the concord and amity for which he had unceasingly striven had now become a reality (loud cheers).” The conception which it is so troublesome to apprehend is not “reality” but “reality (loud cheers)”. Let us first examine the definition according to the purely scientific usage of the word, although it will not take us far enough. The only subject presented to me for study is the content of my consciousness. You are able to communicate to me part of the content of your consciousness which thereby becomes accessible in my own. For reasons which are generally admitted, though I should not like to have to prove that they are conclusive, I grant your consciousness equal status with my own; and I use this second-hand part of my consciousness to “put myself in your place”. Accordingly my subject of study becomes differentiated into the contents of many consciousnesses, each content constituting a view-point. There then arises the problem of combining the view-points, and it is through this that the external world of physics arises. Much that is in any one consciousness is individual, much is apparently alterable by volition; but there is a stable element which is common to other consciousnesses. That common element we desire to study, to describe as fully and accurately as [Pg 284] possible, and to discover the laws by which it combines now with one view-point, now with another. This common element cannot be placed in one man’s consciousness rather than in another’s; it must be in neutral ground—an external world.