Kinds, and sameness of kind—­what colossally useful denkmittel for finding our way among the many!  The manyness might conceivably have been absolute.  Experiences might have all been singulars, no one of them occurring twice.  In such a world logic would have had no application; for kind and sameness of kind are logic’s only instruments.  Once we know that whatever is of a kind is also of that kind’s kind, we can travel through the universe as if with seven-league boots.  Brutes surely never use these abstractions, and civilized men use them in most various amounts.

Causal influence, again!  This, if anything, seems to have been an antediluvian conception; for we find primitive men thinking that almost everything is significant and can exert influence of some sort.  The search for the more definite influences seems to have started in the question:  “Who, or what, is to blame?”—­for any illness, namely, or disaster, or untoward thing.  From this centre the search for causal influences has spread.  Hume and ‘Science’ together have tried to eliminate the whole notion of influence, substituting the entirely different denkmittel of ‘law.’  But law is a comparatively recent invention, and influence reigns supreme in the older realm of common sense.

The ‘possible,’ as something less than the actual and more than the wholly unreal, is another of these magisterial notions of common sense.  Criticize them as you may, they persist; and we fly back to them the moment critical pressure is relaxed.  ‘Self,’ ‘body,’ in the substantial or metaphysical sense—­no one escapes subjection to those forms of thought.  In practice, the common-sense denkmittel are uniformly victorious.  Everyone, however instructed, still thinks of a ‘thing’ in the common-sense way, as a permanent unit-subject that ‘supports’ its attributes interchangeably.  No one stably or sincerely uses the more critical notion, of a group of sense-qualities united by a law.  With these categories in our hand, we make our plans and plot together, and connect all the remoter parts of experience with what lies before our eyes.  Our later and more critical philosophies are mere fads and fancies compared with this natural mother-tongue of thought.

Common sense appears thus as a perfectly definite stage in our understanding of things, a stage that satisfies in an extraordinarily successful way the purposes for which we think.  ‘Things’ do exist, even when we do not see them.  Their ‘kinds’ also exist.  Their ‘qualities’ are what they act by, and are what we act on; and these also exist.  These lamps shed their quality of light on every object in this room.  We intercept it on its way whenever we hold up an opaque screen.  It is the very sound that my lips emit that travels into your ears.  It is the sensible heat of the fire that migrates into the water in which we boil an egg; and we can change the heat into coolness by dropping in a lump of ice.  At this stage of philosophy all non-European men without exception have remained.  It suffices for all the necessary practical ends of life; and, among our own race even, it is only the highly sophisticated specimens, the minds debauched by learning, as Berkeley calls them, who have ever even suspected common sense of not being absolutely true.