Universa Philosophia

A sign, which through cognition of itself makes us come into cognition of the thing signified through it; one is purely intellectual, because it is perceived by the intellect alone: another is sensible, because it is perceived by an external sense. Which is excellently defined by Blessed Augustine: A sign is what, besides the species which it brings into the senses, makes us come into cognition of another thing. There the word species can be taken either for the impressed species, which the sensible object throws into the senses: or better for the sensation itself, which Augustine rightly calls species, because since it is cognition produced in the sense, it is the expressed species, and the formal image of the object. Besides this cognition, the sign causes another, namely cognition of the thing signified, smoke for example, or the footprint of an animal, moves the sense to cognition of itself. From which sensation the intellect is aroused, and knows the smoke and the footprint: which once known is moved through cognition of the smoke to cognition of fire, and through cognition of the footprint to cognition of the animal: and so two cognitions arise from this sign, one about the sign itself, the other about the signified thing.