Comte, therefore, here breaks with Descartes who conceived biology as a prolongation of physics. He takes an entirely different view of this science, which, in a sense, is opposed to the whole of the sciences of the inorganic world. From this there arises a double effort. On the one hand, Comte wishes to maintain the continuity of the encyclopædic series of the sciences: he thus shows Biology as immediately following chemistry, and maintaining the closest relations with astronomy and physics. On the other hand he clearly brings out the irreducible character of the vital phenomena, and the modifications which the positive method must undergo when applied to them. Despite the extreme difference between the points of view and the doctrines, he often makes us think of those deep and difficult passages in the _Critique du Jugement_ where Kant has shown that without the hypothesis of an inner finality, (although this hypothesis is in itself obscure), the phenomena which take place in living beings remain unintelligible. With biology, says Comte, necessarily appear the ideas of _consensus_, of hierarchy, of “milieu”, of the conditions of existence, of the relation between the static and the dynamic states, between the organ and the function.[154] In a word, a biological phenomenon, considered alone is devoid of meaning. Strictly speaking, it does not even exist. It can only be understood by its relations with the other phenomena which take place in the living being, phenomena which react upon it. At the same time it reacts upon them. Here, in opposition to what takes place in the inorganic world, the parts are only intelligible through the idea of the whole. Undoubtedly a certain solidarity of phenomena exists in the inorganic world, which allows us to consider united wholes in it. But the solidarity of biological phenomena is far closer, for, without it we could not conceive them, while, as regards the phenomena of the inorganic world, there is nothing impossible in this abstraction. Henceforth, the positive method must adapt itself to the characteristics which belong to biological phenomena. It does not always demand, as it has been wrongly stated, that we should go from the simple to the complex, but only that we should proceed from the known to the unknown. It is true that in the sciences of the inorganic world we proceed from the least complex to the most complex cases; we begin by the study of phenomena which are as isolated as possible from one another. But, on the contrary, living beings are all the better known to us in proportion as they are more complex. The idea of the animal is in some respects clearer to us than the idea of the vegetable. The idea of the superior animals is clearer to us than that of the inferior ones. Finally man for us is the principal biological unity, and it is from this unity that speculation starts in this science.