The Spirits' Book
Book One - First Causes
Chapter II - General Elements of the Universe
Properties of Matter
32. According to this interpretation, are favors, odors, colors, sounds, and the toxic or beneficial qualities of bodies solely the result of modifications of the same basic substance?
“Precisely. These senses only exist according to the design of the organs intended to perceive them.”
This principle is demonstrated by the fact that everyone does not perceive the qualities of material items in the same manner. While something may appear to taste good to one person, it may be horrible to another; what appears blue to one person appears red to another. That which is poisonous for some, is harmless or even healthy for others.