[Footnote: Ideology is now sometimes used to convey a criticism; for instance, to contrast the methods of Lamarck with those of Darwin.] Ideology, the science of ideas, was the word invented by de Tracy to distinguish the investigation of thought in accordance with the methods of Locke and Condillac from old-fashioned metaphysics.

The guiding principle of the ideologists was to apply reason to observed facts and eschew a priori deductions.

Thinkers of this school had an influential organ, the Decade philosophique, of which J.B.Say the economist was one of the founders in 1794.

The Institut, which had been established by the Convention, was crowded with "ideologists," and may be said to have continued the work of the Encyclopaedia.

[Footnote: Picavet, op.cit.p.69.The members of the 2nd Class of the Institut, that of moral and political science, were so predominantly Ideological that the distrust of Napoleon was excited, and he abolished it in 1803, distributing its members among the other Classes.] These men had a firm faith in the indefinite progress of knowledge, general enlightenment, and "social reason." 2.
Thus the ideas of the "sophists" of the age of Voltaire were alive in the speculative world, not withstanding political, religious, and philosophical reaction.