ment that as late as his twelfth year he was still unable to read. His education began only in his teens, first under the direction of a local priest, then at Lyons, where he went to live with his older brother, Jean, after the death of their father. Perhaps because of his reticence and his late learning his family regarded him as possessing limited intellectual abilities. He nonetheless managed to continue his education as a seminarian in Paris, at Saint-Suplice and at the Sorbonne. He took holy orders in 1740 and wore a cassock for the rest of his life, but did no pastoral work. After some years spent living the life of a man of letters in Paris, during which he came to be closely acquainted with Rousseau and Diderot, and published work that won him election to the Prussian Academy of the Sciences (1749), he accepted a position as tutor to the Prince of Parma, a post that he held from 1758–68. He returned to Paris in 1768 and was elected to the French Academy in that year, but he left the city shortly after, in 1773, and took up residence on a country estate he had purchased near Beaugency. He died there on August 3, 1780.
Condillac published two main philosophical works: the Essay on the Origin of Human Knowledge of 1746, and the Treatise on Sensations of 1754, both of which were devoted to expositing his views on the role of experience in the development of our cognitive capacities.
The earlier Essay was a less radical work. Though it sought to explain how the cognitive faculties are developed as a consequence of sensation, it took sensation itself largely for granted. Condillac explicitly rejected the views that the mind can make judgments that it is not aware of, and that we can confuse the products of inferential operations with immediately given sensations. As a consequence, he maintained, in opposition to Molyneux, Locke, and Berkeley, that we do not need to learn to perceive visual depth. However, the Essay was also more wide-ranging than the Treatise. It devoted attention to the development of language and its role both in the acquisition of our more sophisticated cognitive powers and in the generation of false philosophies. These are topics that Condillac later relegated to his works on logic.
In the Treatise Condillac focused just on our pre-linguistic cognitive abilities, which he came to think he might have underestimated when he wrote the Essay. He retracted his earlier claim that perception is a transparent process and accepted both that it involves unconscious inference from what is given in sensation and that sensation itself may contain more than it is at first perceived to contain. He also retracted his earlier claim that depth is immediately perceived by vision. To support these revised opinions, he proposed a famous thought experiment. He asked his readers to consider an originally inanimate and insentient human being (Condillac spoke of a being that is just a “statue” of a human being) and to consider what this being could come to know were it to acquire each of the senses in isolation from the others, or each in combination with just one or two others. In proposing this question Condillac was asking a more radical version of the question Molyneux had posed to Locke: would a person born blind and made to see perceive spatial features well enough upon first sight to be able to identify cubes and spheres without touching them? Condillac was asking what a person endowed with just a sense of smell would think upon acquiring the power of hearing, or what a person endowed with vision would know if unaffected by hunger, incapable of motion, and unaware of any tactile sensation. His answer to these questions sought not just to explain how this person would acquire ideas of space and of external objects, but to prove that nothing more would be needed for it to acquire all the knowledge and all of the abilities that we have other than just to experience a sufficiently rich array of sensations.
Condillac's other philosophical works support and embellish the doctrines of the Essay and the Treatise. They are t