The philosopher, George Berkeley, famously asserted that we cannot see distance. Our eyes can only see in 2-dimensions. However, we manage to navigate in a 3-dimensional world pretty well. 3-dimensional seeing then, is a learnt skill. This conclusion has radical implications for the possible development of perception to new and novel places, writes Kenneth L. Pearce.

John Locke credits the Irish philosopher and vision scientist William Molyneux (1656–1698) with posing the following ‘problem’:

Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere of the same metal, and nighly [nearly] of the same bigness, so as to tell, when he felt one and the other, which is the cube, which the sphere. Suppose then the cube and sphere placed on a table, and the blind man be made to see: Quaere [Question], “whether by his sight, before he touched them, he could now distinguish and tell, which is the globe, which the cube?” (Essay concerning Human Understanding, §2.9.8)