By external purposiveness I mean that by which one thing of nature serves another as means to a purpose. Now things which have no internal purposiveness and which presuppose none for their possibility, e.g. earth, air, water, etc., may at the same time be very purposive externally, i.e. in relation to other beings. But these latter must be organised beings, i.e. natural purposes, for otherwise the former could not be judged as means to them. Thus water, air, and earth cannot be regarded as means to the raising of mountains, because mountains contain nothing in themselves that requires a ground of their possibility according to purposes, in reference to which therefore their cause can never be represented under the predicate of a means (as useful therefor).
External purposiveness is a quite different concept from that of internal purposiveness, which is bound up with the possibility of an object irrespective of its actuality being itself a purpose. We can ask about an organised being the question: What is it for? But we cannot easily ask this about things in which we recognise merely the working of nature’s mechanism. For in the former, as regards their internal possibility, we represent a causality according to purposes, a creative Understanding, and we refer this active faculty to its determining ground, viz. design. There is only one external purposiveness which is connected with the internal purposiveness of organisation, and yet serves in the external relation of a means to a purpose, without the question necessarily arising, as to what end this being so organised must have existed for. This is the organisation of both sexes in their mutual relation for the propagation of their kind; since here we can always ask, as in the case of an individual, why must such a pair exist? The answer is: This pair first constitutes an organising whole, though not an organised whole in a single body.
If we now ask, wherefore anything is, the answer is either: Its presence and its production have no reference at all to a cause working according to design, and so we always refer its origin to the mechanism of nature, or: There is somewhere a designed ground of its presence (as a contingent natural being). This thought we can hardly separate from the concept of an organised thing; for, since we must place at the basis of its internal possibility a causality of final causes and an Idea lying at the ground of this, we cannot think the existence of this product except as a purpose. For the represented effect, the representation of which is at the same time the determining ground of the intelligent cause working towards its production, is called a purpose. In this case therefore we can either say: The purpose of the existence of such a natural being is in itself; i.e. it is not merely a purpose but a final purpose, or: This is external to it in another natural being, i.e. it exists purposively not as a final purpose, but necessarily as a means.
But if we go through the whole of nature we find in it, as nature, no being which could make claim to the eminence of being the final purpose of creation; and we can even prove a priori that what might be for nature an ultimate purpose, according to all the thinkable determinations and properties wherewith one could endow it, could yet as a natural thing never be a final purpose.
If we consider the vegetable kingdom we might at first sight, on account of the immeasurable fertility with which it spreads itself almost on every soil, be led to take it for a mere product of that mechanism which nature displays in the formations of the mineral kingdom. But a more intimate knowledge of its indescribably wise organisation does not permit us to hold to this thought, but prompts the question: What are these things created for? If it is answered: For the animal kingdom, which is thereby nourished and has thus been able to spread over the earth in genera so various, then the further question comes: What are these plant-devouring animals for? The answer would be something like this: For beasts of prey, which can only be nourished by that which has life. Finally we have the question: What are these last, as well as the first-mentioned natural kingdoms, good for? For man, in reference to the manifold use which his Understanding teaches him to make of all these creatures. He is the ultimate purpose of creation here on earth, because he is the only being upon it who can form a concept of purposes, and who can by his Reason make out of an aggregate of purposively formed things a system of purposes.
We might also with the chevalier Linnaeus[123] go the apparently opposite way and say: The herbivorous animals are there to moderate the luxurious growth of the vegetable kingdom, by which many of its species are choked. The carnivora are to set bounds to the voracity of the herbivora. Finally man, by his pursuit of these and his diminution of their numbers, preserves a certain equilibrium between the producing and the destructive powers of nature. And so man, although in a certain reference he might be esteemed a purpose, yet in another has only the rank of a means.
If an objective purposiveness in the variety of the genera of creatures and their external relations to one another, as purposively constructed beings, be made a principle, then it is conformable to Reason to conceive in these relations a certain organisation and a system of all natural kingdoms according to final causes. Only here experience seems flatly to contradict the maxims of Reason, especially as concerns an ultimate purpose of nature, which is indispensable for the possibility of such a system and which we can put nowhere else but in man. For regarding him as one of the many animal genera, nature has not in the least excepted him from its destructive or its productive powers, but has subjected everything to a mechanism thereof without any purpose.
The first thing that must be designedly prepared in an arrangement for a purposive complex of natural beings on the earth would be their place of habitation, the soil and the element on and in which they are to thrive. But a more exact knowledge of the constitution of this basis of all organic production indicates no other causes than those working quite undesignedly, causes which rather destroy than favour production, order, and purposes. Land and sea not only contain in themselves memorials of ancient mighty desolations which have confounded them and all creatures that are in them; but their whole structure, the strata of the one and the boundaries of the other, have quite the appearance of being the product of the wild and violent forces of a nature working in a state of chaos. Although the figure, the structure, and the slope of the land might seem to be purposively ordered for the reception of water from the air, for the welling up of streams between strata of different kinds (for many kinds of products), and for the course of rivers—yet a closer investigation shows that they are merely the effects of volcanic eruptions or of inundations of the ocean, as regards not only the first production of this figure, but, above all, its subsequent transformation, as well as the disappearance of its first organic productions.[124] Now if the place of habitation of all these creatures, the soil (of the land) or the bosom (of the sea), indicates nothing but a quite undesigned mechanism of its production, how and with what right can we demand and maintain a different origin for these latter products? The closest examination, indeed (in Camper’s[125] judgement), of the remains of the aforesaid devastations of nature seems to show that man was not comprehended in these revolutions; but yet he is so dependent on the remaining creatures that, if a universally directing mechanism of nature be admitted in the case of the others, he must also be regarded as comprehended under it; even though his Understanding (for the most part at least) has been able to deliver him from these devastations.
But this argument seems to prove more than was intended by it. It seems to prove not merely that man cannot be the ultimate purpose of nature, and that on the same grounds the aggregate of the organised things of nature on the earth cannot be a system of purposes; but also that the natural products formerly held to be natural purposes have no other origin than the mechanism of nature.
But in the solution given above of the Antinomy of the principles of the mechanical and teleological methods of production of organic beings of nature, we have seen that they are merely principles of the reflective Judgement in respect of nature as it produces forms in accordance with particular laws (for the systematic connexion of which we have no key). They do not determine the origin of these beings in themselves; but only say that we, by the constitution of our Understanding and our Reason, cannot conceive it in this kind of being except according to final causes. The greatest possible effort, even audacity, in the attempt to explain them mechanically is not only permitted, but we are invited to it by Reason; notwithstanding that we know from the subjective grounds of the particular species and limitations of our Understanding (not e.g. because the mechanism of production would contradict in itself an origin according to purposes) that we can never attain thereto. Finally, the compatibility of both ways of representing the possibility of nature may lie in the supersensible principle of nature (external to us, as well as in us); whilst the method of representation according to final causes may be only a subjective condition of the use of our Reason, when it not merely wishes to form a judgement upon objects as phenomena, but desires to refer these phenomena together with their principles to their supersensible substrate, in order to find certain laws of their unity possible, which it cannot represent to itself except through purposes (of which the Reason also has such as are supersensible).