The world around us [said Kant] opens before our view so magnificent a spectacle of order, variety, beauty, and conformity to ends that, whether we pursue our observations into the infinity of space in the one direction, or into its illimitable divisions in the other, whether we regard the world in its greatest or its least manifestations—even after we have attained to the highest summit of knowledge which our weak minds can reach—we find that language in the presence of wonders so inconceivable has lost its force, and numbers its power to reckon; nay, even thought fails to conceive adequately, and our conception of the whole dissolves into an astonishment without the power of expression—all the more eloquent that it is dumb. Everywhere around us we observe a chain of causes and effects, of means and ends, of death and birth; and as nothing has entered of itself into the condition in which we find it, we are constantly referred to some other thing, which itself suggests the same inquiry regarding its cause, and thus the universe must sink into the abyss of nothingness unless we admit that, besides this infinite chain of contingencies, there exists something that is primal and self-subsistent, something which as the cause of this phenomenal world secures its continuance and preservation.
In our appreciation of this striking passage we must, however, bear in mind that Kant regarded the notion of design or purpose as regulative and not constitutive. We can go no further than saying that, as regulative, the notion permits us to regard all connection between phenomena as if it was the expression of purpose. It is purposive for us; not necessarily purposive in its inner constitution. The best way, it has been said by one of Kant's interpreters, to simplify and systematise our multiplex experiences is to proceed as though such conceptions as that of purpose in nature were valid. We may accept them as postulates, and wonderful order will follow; but we are not entitled to state them as dogmas. We most of us accept, and not least those who pride themselves on being eminently practical and hard-headed, the reality of the things around us as given in sensory experience. But they are realities for the conduct of the affairs of daily life: they are realities for us constituted as we are; they too are regulative and not constitutive. Practical folks who have taken the trouble to grasp this fact should raise no objection to the contention that reality of purpose in nature is of precisely the same kind. They may deny its existence on other grounds; but on these grounds no valid exception can be taken to Kant's position. We daily and hourly act as if the world around us had a constitutive reality independent of our own experience. And it is unquestionable that we also act as if there were an orderly purpose in the operations of nature to which our own purposes must be adjusted if we would escape disastrous consequences. Fret as we may at the fact, we do not and cannot know the constitutive reality of the universe. But some of us believe that the conception of purpose, as regulative, is for rational thought, not less valid than that of the mechanism through which it finds expression. In any case Kant was definitely of opinion that naturalistic interpretations are, taken by themselves, insufficient. "It is quite certain," he said, " that we cannot adequately cognise, much less explain, organised beings and their internal possibility according to mere mechanical principles of nature." And Lotze, who fearlessly applied the interpretation of naturalism, even within the domain of organic life, urged that the function of mechanism in the universe is entirely subordinate, and must be regarded philosophically as the instrument of purpose.
Accepting, therefore, the notion of purpose as a postulate, as a regulative principle of our thought, the question arises by what right we project it on to the plane of objective existence. In the first place it must be remembered that objective existence is part and parcel of our experience, and that our highest thought is for naturalism but an elaboration of that experience. The question then comes to this: Does purpose underlie and rationalise our thought and experience? If it does not, then nowhere does it exist save as a convenient fiction, though a fiction with which we find it difficult to dispense. If it does, then it must underlie the perceptions of daily life and the conceptions of science in their objective reference, that is to say as projected on to the plane of the nature we interpret. In the second place, supposing that we grant that determining purpose is a real factor in human thought, then since that thought is, for naturalism, a product of evolution which is essentially one and continuous, it is only the final term of a purpose that has been operative throughout the whole course of that evolution. It is just because I believe that all that science discloses is the manifestation of a continuous purpose that I believe that the manifestation is itself continuous, and that the origin of life and mind are ideally capable of explanation in terms of antecedence, coexistence, and sequence.
But what is the criterion of purpose? Let us first consider its manifestation in human life and thought, and as therein susceptible of treatment under the canons of scientific interpretation. A strictly naturalistic discussion of volition, such as that of which we have already given an outline, discloses all the essential features of the process. There is first of all an idea of the end to be attained, and we speak of this as prevision. There is last a presentation of the end as attained. That is all. It is true that between first and last there may be an indefinite number of stages which we speak of as the means by which the end is gradually attained. But every stage is susceptible of a like analysis into an intermediate end first foreseen and then attained. In naturalistic interpretation that is all. Association explains everything. Why the foreseen end should pass into the end as attained we may not ask, or, if we ask, naturalism perse affords no answer. It states the observed fact that it is so, such being the inherent constitution of things and thoughts. What then is the essential feature? That the end or sequent is implicitly contained in the antecedent prevision. This is the naturalistic interpretation of volition. So, too, with our inferences as rational. Dr. Bosanquet has drawn attention to the paradox of inference— that we have not inference unless the conclusion is both necessary from the premises and goes beyond the premises. But it is in the premises implicitly, and goes beyond them only in being rendered explicit. So that here again the sequent is implicitly contained in the antecedent conditions just in so far as determinism holds good. Now I accept such views as sufficient for a naturalistic psychology and logic. But I raise the question whether, granting this to be all that is presented to experience, it is all that is given in experience; whether, granting that this is an adequate analysis of a manifestation of purpose, we are not aware of the underlying purpose as thus manifested. To make my meaning clear I may again quote Dr. Pringle-Pattison's criticism of the naturalistic treatment of volition. In it there is, he says, "first the idea of a movement as in contemplation, and secondly the perception of the movement as executed. In other words, there is a series of happenings somehow passing before us, but no real activity, no real actor in the whole affair." This he contends is incredible, and why? Because the perfectly legitimate method of science in its dealing with the facts of antecedence and sequence as simply given data needs to be supplemented by the conception of agency; the determinate sequence implies, for metaphysics if not for science as such, a determining cause. The whole question resolves itself into, first, the acceptance or not of efficient causation underlying the given antecedence and sequence, and, secondly, if we accept such causal agency as a postulate of reason, our awareness or not of its presence. Here is the point of divergence between different schools of thought. I myself accept the postulate of causation ; and I certainly seem (to put it in the least dogmatic form)—I certainly seem to be aware of its operation within my consciousness. But if purpose, as causal, is that of which my volitional sequences are the expression, and if these sequences are continuous with those in evolution at large, then are all sequences throughout the universe the manifestation of purpose.