Here, says Comte, is the only exception to the encyclopædic law according to which the more general phenomena control the more particular ones without being influenced by them.[126] From this he simply concludes that the phenomena of our system are the most general to which positive research can extend, and that the study of the universe must henceforth be excluded from natural philosophy. The encyclopædic law then remains true for the whole of positive philosophy. The delimitation of the object of astronomy is one of the points where we can best follow the successive modifications of Comte’s thought. In the second volume of the _Cours de philosophie positive_ he gave to astronomy the place which is generally conceded to it by scientific men. He even claims, as a condition for its utility, the most perfect disinterestedness of scientific research in the whole extent of its province. The example which he gives of it (the determination of longitude at sea), is borrowed from Condorcet. Undoubtedly, Comte already insists upon the distinction between the ideas of world and universe, the former only being positive. Nevertheless, he still admits that we should not give up all hope of obtaining some sidereal knowledge,[127] and that it would be very precious for us to know the relative motions of multiple stars, etc. But already in the sixth volume of the _Cours_ he condemns entirely the “so-called sidereal astronomy, which to-day constitutes the only grave scientific aberration peculiar to celestial studies.”[128] Ten years later, in the first volume of the _Politique positive_, he “regenerates” astronomy from the synthetic point of view. He is no longer content to limit it to the knowledge of the solar system. He confines the particular study of our world within narrow limits. Astronomy, like the other sciences, from objective must become subjective. Instead of the vague (that is to say indefinite) study of the heavens its end must be the knowledge of the earth, and the consideration of the other celestial bodies only in their relation to the human planet. At this price alone can the unity of this science be secured.[129]