The semantic parallelism between the various kinds of Sense Verbs is usually unnoticeable lexically in the chemical and tactile senses; these sentences all use the same verb in each construction:
- She tasted/smelled/felt it on purpose. (Volitional agent subject)
- He tasted/smelled/felt it by accident. (Non-Volitional perceiver subject)
- They both agreed that it tasted/smelled/felt really weird. (Flip subject)
But sound and vision have more verbs, because we get more information from them. Interestingly, sound -- the medium of language -- distinguishes each of these construction types with a different verb, listen (with a preposition if transitive), hear, and sound. Vision has only two distinctive verbs, look (with a preposition if transitive) and see.
- She looked at/listened to it on purpose.
- He saw/heard it by accident.
- They both agreed that it looked/sounded really weird.
So, for sound and vision only, there is an implicative relation
between the volitional look at/listen to and the perceptual see/hear. That is,
P looks at/looked at X entails
P sees/saw X
P listens to/listened to X entails
P hears/heard X
I.e, if you listened to it, you heard it; and if you looked at it, you saw it.
Generally one uses the perceptual verb only if one can't use the volitional one that entails it.
The examples given in the OQ -- You look, but you don't see, for instance -- use intransitive look. That's rather different, because it doesn't necessarily entail see. In context, intransitive look means try to look, which makes sense. Ditto for intransitive listen in You listen, but you don't hear.
And, finally, note that look, listen, see, and hear are not being used literally in these examples. The speaker does not refer to the literal sense of sight or sound, but rather, metaphorically, to thought. For look and see, one of the most prominent metaphorical themes uses light as a metaphor for thought, e.g,
- She's brilliant, he's pretty bright, they're real stars.
For listen, hear, and sound, the metaphor is simpler --
Language. Not true, but metaphors never are. Since you can hear something but not understand it, these metaphoric verbs fit nicely into the proverb. It should also be noted that this is not a normal use or meaning for sense verbs, though they do participate in a lot of idioms and strange constructions.