Why does Thucydides prefer the less scientific and more subjective terms for cause? It is not possible to return to Cornford's view that Thucydides did not understand cause as such but only grievances, pretexts, and the like, for the way in which he uses aitiai contradicts this supposition. If he can explain the smallness of the Trojan expedition (I, 11, 1) objectively, scientifically, even with an obvious awareness of the causative force of economic factors, we cannot suppose him to have been unable to express the causes of the Peloponnesian war in the same spirit, had he chosen to.