And he anticipated Comte's famous "law" of the three stages of intellectual evolution, though without giving it the extensive and fundamental significance which Comte claimed for it.

"Before man understood the causal connection of physical phenomena, nothing was so natural as to suppose they were produced by intelligent beings, invisible and resembling ourselves; for what else would they have resembled ?" That is Comte's theological stage.

"When philosophers recognised the absurdity of the fables about the gods, but had not yet gained an insight into natural history, they thought to explain the causes of phenomena by abstract expressions such as essences and faculties." That is the metaphysical stage.

"It was only at a later period, that by observing the reciprocal mechanical action of bodies hypotheses were formed which could be developed by mathematics and verified by experience." There is the positive stage.

The observation assuredly does not possess the far-reaching importance which Comte attached to it; but whatever value it has, Turgot deserves the credit of having been the first to state it.
The notes which Turgot made for his plan permit us to conjecture that his Universal History would have been a greater and more profound work than the Essay of Voltaire.