Near the end of Kant's Critique of Judgement, he wrestles with the question of whether or not “all production of material things is possible according to merely mechanical laws.” This explores whether it is necessary to invoke something more than mechanism (not necessarily God, but something more) in the explanation of how everything in the world came to be the way that it is.
He draws upon his distinction between reflective judgement (i.e. aesthetic taste) and determinant judgement (i.e. empirical knowledge) to show that this question comes out differently according to one's focus. From the point of view of aesthetics, he acknowledges that it is “a quite correct fundamental proposition” that “there must be thought a causality distinct from that of mechanism”, namely “an (intelligent) cause of the world acting in accordance with purposes”. But this is solely from the perspective of the reflective judgement, and therefore from the viewpoint of the arts.
From the perspective of the empirical knowledge, however, Kant states that “this would be a hasty and unprovable proposition.” Whatever our aesthetic sensibilities suggest, “we by no means undertake to concede reality” to something that is at root “a mere Idea”. Whatever our instincts in this regard, the interpretation of the origins of the world is “always open to all mechanical grounds of explanation”, and to follow where our sense of aesthetics leads would be to withdraw “beyond the realm of Sense into the transcendent” and possibly to be “led into error”.
Kant explores all the major perspectives on this issue that are available at his time, and rejects them all. He grants to theism (the last interpretation he considers) one small concession, namely that “ it certainly is superior to all other grounds of explanation” in so much as “rescues in the best way the purposiveness of nature” from intellectual irrelevance by introducing “a causality acting with design for its production.” His thrust, here, is to grant that at least the theists offer some possible explanation for the appearance of purpose in nature, which no-one else at his time was really able to address.
But this, he insists, isn't enough for the theistic interpretation to win out. In order for it to do so, it would be necessarily to “prove satisfactorily... the impossibility of the unity of purpose in matter resulting from its mere mechanism”. The idea of God as the origin of purpose in nature – the theistic instantiation of the claim of intelligent design – is not empirically valid in and of itself, and “can justify absolutely no objective assertion.” Once again, Kant says our aesthetic sense may accord with the idea of an intelligent designer, but we cannot validate this impression objectively. Nonetheless, he admits once again that we are “indispensably obliged to ascribe the concept of design to nature if we wish to investigate it.” As observed last week, we simply cannot think about organisms viably without recourse to the concept of design, even if we reject the idea of a designer as the explanation behind this.
Yet despite Kant's denial of intelligent design as empirically valid (i.e. as relevant for science), he falls considerably short of shooting down intelligent design as a belief. In fact, he suggests that the presence of natural purposes (i.e. organisms) represents “the only valid ground of proof for [the] dependence on and origin from a Being existing outside the world”, a being who once inferred must also be intelligent, else such a being does not contribute to an explanation of the apparent presence of purpose in nature. He ultimately concludes that “Teleology then finds the consummation of its investigations only in Theology.” Which is to say that Kant does not want to allow any role for the provision of ultimate purposes in science at all, and considers this a more suitable subject for theologians than in empirical research.
Kant reiterates this point by comparing the premature claim one might wish to make with all that one can reasonably assert in this regard:
If we expressed this proposition dogmatically as objectively valid, it would be: “There is a God.” But for us men there is only permissible the limited formula: “We cannot otherwise think and make comprehensible the purposiveness which must lie at the bottom of our cognition of the internal possibility of many natural things, than by representing it and the world in general as a product of an intelligent cause, [a God].”
So Kant says in effect that we must think in terms of a designer (because we can think of organisms in no other way), but this doesn't mean that there must be one objectively. This tallies nicely with our modern perspective on evolution, which continues to think of organisms as being designed, often subconsciously, but does not permit any de facto claim for the objective existence of a designer i.e. a necessary Creator god. Evolutionary thinking posits the designer in question as natural selection and related mechanisms – but interestingly, following Kant's reasoning, we should still question this deployment of an abstract idea – “Evolution” – in the role of designer. We can easily be mislead by the lure of teleology into unwarranted conclusions.
For since we do not, properly speaking, observe the purposes in nature as designed, but only in our reflection upon its products think this concept as a guiding thread for our Judgement, they are not given to us through the object.
And this criticism applies to evolutionary beliefs as much as it applies to intelligent design! The sum of our empirical knowledge of natural selection does not in and of itself validate claims of the form that such-and-such a feature evolved for such-and-such a purpose. Evolutionary perspectives deny the intelligence aspect of the origin of organisms, but they do not successfully evade the design part – they couch the appearance of designed features in terms of selection effects and so forth, but there is still in all such thinking a teleology, an appeal to an ultimate cause that is then used to evince explanations. As I have observed previously, teleological games play the same regardless of one's justifying principle, and this should make us suspicious of such claims.
If, as Kant's reasoning suggests, intelligent design must be excluded from science classes since it is not founded in empirical observations, then certain beliefs concerning the metaphysical implications of evolutionary theories are equally barred. If a teleology that culminates in God is not allowable for science, neither is a teleology that ends in something else – even natural selection. The jump to the conclusion that “natural selection is the ultimate cause of everything in existence” (which certain people do advocate) is not empirical grounded, and to advance such a viewpoint is, Kant affirms, to take a theological position – albeit one taking the “anti” rather than the “pro” God position. Neither viewpoint is strictly appropriate for a science curriculum – and this suggests an equitable boundary on what science teachers may teach their students, irrespective of their own teleological beliefs.
Next week, the final part: Kant on Darwin