Aristotle

Hearing. A statement of his, "Man cannot be a subject of instruction otherwise than through the ear", was interpreted for over two thousand years as meaning that born-deaf people could not be educated at all. Since people considered Aristotle to be a major authority, this seriously damaged and retarded deaf people for more than two milennia. Modern scholars think that Aristotle did not mean this sentence literally. Aristotle also linked speech with the soul, since animals did not have either speech or souls. This led to the additional damaging inference that non-speaking people did not have souls, or only damaged souls. Hence, the early Christian Church and contemporary society paid almost no attention to born-deaf people, considering them little better than animals.