Doth the reality of sensible things consist in being perceived? Or is it something distinct from their being perceived, and that bears no relation to mind?
Here Philonous presents his famous claim that, when it comes to sensible objects (i.e. objects we can immediately experience through our sensory faculties), esse is percipi — that is, their existence is to be perceived. Such objects do not have any mind-independent existence. They exist if they are perceived, and they do not exist if they are not perceived.