But, after what we have just seen,--namely, the part played by voluntary attention in volition,--a belief in free will and purely spiritual causation is still open to us. The duration and amount of this attention _seem_ within certain limits indeterminate. We _feel_ as if we could make it really more or less, and as if our free action in this regard were a genuine critical point in nature,--a point on which our destiny and that of others might hinge. The whole question of free will concentrates itself, then, at this same small point: "Is or is not the appearance of indetermination at this point an illusion?" It is plain that such a question can be decided only by general analogies, and not by accurate observations. The free-willist believes the appearance to be a reality: the determinist believes that it is an illusion. I myself hold with the free-willists,--not because I cannot conceive the fatalist theory clearly, or because I fail to understand its plausibility, but simply because, if free will _were_ true, it would be absurd to have the belief in it fatally forced on our acceptance. Considering the inner fitness of things, one would rather think that the very first act of a will endowed with freedom should be to sustain the belief in the freedom itself. I accordingly believe freely in my freedom; I do so with the best of scientific consciences, knowing that the predetermination of the amount of my effort of attention can never receive objective proof, and hoping that, whether you follow my example in this respect or not, it will at least make you see that such psychological and psychophysical theories as I hold do not necessarily force a man to become a fatalist or a materialist. Let me say one more final word now about the will, and therewith conclude both that important subject and these lectures. There are two types of will. There are also two types of inhibition. We may call them inhibition by repression or by negation, and inhibition by substitution, respectively. The difference between them is that, in the case of inhibition by repression, both the inhibited idea and the inhibiting idea, the impulsive idea and the idea that negates it, remain along with each other in consciousness, producing a certain inward strain or tension there: whereas, in inhibition by substitution, the inhibiting idea supersedes altogether the idea which it inhibits, and the latter quickly vanishes from the field.