Full Idea
A man with touch, taste and smell, but no hearing or sight, will assume nothing audible or visible exists, so maybe an apple has qualities which we have no senses to perceive.
Gist of Idea
If we had no hearing or sight, we would assume no sound or sight exists, so there may be unsensed qualities
Source
Sextus Empiricus (Outlines of Pyrrhonism [c.180], I.96)
Book Reference
Sextus Empiricus: 'Outlines of Pyrrhonism', ed/tr. Bury,R.G. [Prometheus 1990], p.44