Sensationism, Progress, and French Materialism

Étienne Bonnot de Condillac (1714-1780) radicalized Locke's empiricism into a fully sensationist theory of knowledge. In his Essay on the Origin of Human Knowledge (1746) and especially his Treatise on Sensations (1754), Condillac argued that all human faculties — attention, memory, judgment, imagination, even desire — could be derived from sensation alone, without needing to posit, as Locke had, an independent faculty of reflection. To demonstrate this, he devised the celebrated thought experiment of a marble statue, organized internally like a human being but initially devoid of any ideas, which is progressively endowed with the senses one at a time, beginning with smell; Condillac traced, step by step, how such a being would gradually construct the full range of human cognitive and psychological life out of successive and combined sensations alone.