But how do we arrive at any apprehension of Natural Action? What informs us that Nature is a potency ever operative? What suggests to us the conception of potency at all? We reply that we arrive at the idea of potent action because we are ourselves active beings. Our organism maintains itself by constant physiological activities. These are the permanent constancies of transmutation which constitute the organism.
But superimposed upon these there are our voluntary exertional activities. By these latter we necessarily mingle with and indeed participate in the action of the natural forces which (as we usually say) surround us, but which in point of fact do more than surround us. The disparate grouping of natural bodies in vision blinds us to the fact that we are really not merely surrounded by but are mingled with and participate in the dynamic system.[61:1] We are continually pressing with our weight upon the bodies on which we rest, we are continually exerting or resisting the pressure of so-called adhering masses—resistance-points in one dynamic system of which we are ourselves a part. Thus it is that in our exertional action we reveal to our consciousness not only the forms of our own activity but the forms of the dynamic system which contains and yet transcends the Sensible and the Ideal.
The theory we have suggested enables us to proceed at once to a rational explanation of Sensation.
Sensation is obstructed action. A detailed consideration of as many as you like to take of the myriad constituents of our sensible Experience will continually and without exception confirm this simple fact.
In Nature it is the potent action which is real. It alone can be directly represented by the activity of Thought. The mere obstruction of activity is not a real thing, hence the unreal character of Sensation. Yet the obstruction being an obstruction of the real action of Nature is, if not real, at least actual and immediate. Nay, its presence in our Experience, however mutable and unstable it may be, is the only sure test and guarantee of Reality.
Each of the two leading theories which have dominated speculation presents one partial aspect of the truth.
The eternal cognisable element of Reality is apprehended, as the Platonist holds, by the intellect and by the intellect alone. To that extent the Platonist is right. That cognisable element is Action. But Action is denoted for us only in the obstructions which it encounters. These obstructions constitute our World of Sensible Experience, which is therefore for each of us the sure indicator of the Real. In recognising this fact the sensationalist is right in his turn.
Not only does the dynamic conception of Nature enable us to account for Sensation, but it lets us see how the Sensible World becomes a constituent of Experience. It is by and through its obstructions and these only that we featurise or denote our Experience. It is by the breaks, the turnings in the road that we cognise its course. It is by the line of rocks and breakers that we define the shore. But we must not mistake the turnings for the roadway nor the shore for the ocean.
It is in and by our activity that we discover this World of sensible obstructions. The features of the Sensible World correspond therefore to the laws of our exertional activity, but the correspondence is relational, not resemblant. Just so, it is by the reflection of Light that we discover the forms of the obstacle which solid bodies oppose to the radiant undulation. The resultant colours correspond to the form of these obstructions; but the correspondence is relational not resemblant. The same is true of sounds, of tactual sensations, of every other sensible obstacle to pure activity.