Like Descartes, Kant recognised our inherent limitations to know the external world as opposed to the pure ideas produced by our own rational faculty. However, he is more optimistic than the French thinker regarding our intellectual ability to ‘mediate’ our experience of the physical world through the ‘categories’ of the understanding. These categories, like time and space, constitute a grid which makes it possible for us to mentally appropriate the external world by ascribing it a rational meaning. However, if we looked for references to Nature in his works, we should not be surprised not to find any moral position concerning the natural world as the philosopher’s priority is firmly centred on Man and his potential moral progress through a better rational understanding of his duties towards other human beings.

In this respect, it would simply be mistaken to bend the ‘categorical imperative’ and make it apply to some ‘ecological commandment’. If, indeed, the categorical imperative could unreservedly be applied to non-human animals and, by extension, to all the non-conscious organisms constituting the biosphere, then Kantian philosophy would surely consider the protection and preservation of nature as one of its most important foundations, which is clearly not the case. Man’s dignity lies, for Kant, in his respecting his fellow-beings and refraining from inflicting unnecessary pain to non-human creatures, i.e., animals; yet, Kant’s morality does not extend beyond the immediate human realm as the eighteenth-century concept of ‘nature’ had nothing to do with our contemporary notion of ‘environment’ but only referred to an hypothetical ‘state of nature’ and to alleged ‘laws of nature’ regarded by some thinkers as the bedrock of human rights.