senses in the present progressive

[jaw300t]

I've been reading a lot lately about the simple present tense, but I may have
missed relevant stuff on the present progressive, so maybe somebody has said
something like this before, and I've just missed it.  I'm aware of discussion
about verbs of senses (feel, see, smell) in the present progressive being used
specifically to express "temporariness".  I have a hunch that speakers do this
not so much to avail themselves of what the present progressive implies but to
avoid what the simple present might imply.

Bolinger says that the present tense is "timeless", not that it expresses
eternalness, but that it is uncommitted about time.  While it may not express
eternalness, it's the tense of choice if you do want to express eternalness.
The thing is, it doesn't exclude past time or future time.

What I'm saying is, if you use the past tense and say:

He was tall.

then people understand you to mean he's not tall anymore.  You exclude the
present, you exclude the future.  If you use the future tense and say:

He will be tall.

then people understand you to mean he isn't tall yet and he definitely wasn't
tall yesterday or last year.  But if you say:

He is tall.

people assume he was probably tall yesterday and he'll probably be tall
tomorrow too.  The simple present tense just does not exclude the past &
future from the scope of a stative predicate.  So if you say:

I feel blue.

people assume you might well have been blue yesterday and you may expect to
feel blue tomorrow.  If, on the other hand, you say:

I'm feeling blue.

you avoid the timelessness inherent in the simple present tense.

I know there has to be a lot of literature out there on sensory or stative
verbs and the present progressive; can somebody clue me in?

Janet Wilson