When the wax in the soul of any one is deep and abundant, and smooth and perfectly tempered, then the impressions which pass through the senses and sink into the heart of the soul… are also lasting, and minds, such as these, easily learn and easily retain
Plato establishes the foundational depth-psychological metaphor of wax as the soul’s receptive substance, whose quality determines the fidelity of sensory impressions and hence the possibility of knowledge and error.
, Theaetetus, -369thesis