A folk-wisdom metaphor / mental image [duplicate]
Solution 1:
It is common to find different words existing in English to represent a similar idea. It is an essential characteristic of a language with a long history.
To give you some idea: (I have linked the etymologies as well, which could give some idea about the original differences between the words which have deteriorated over time and use.)
Aphorism:
A ‘definition’ or concise statement of a principle in any science (OED)
This is essentially used to refer to a definition in science or any other technical education.
Adage:
A maxim handed down from antiquity (OED)
Any principle bequeathed from the past is an adage.
Proverb:
A short pithy saying in common and recognized use (OED)
A proverb has to be pithy and also common in use.
However we can certainly say that these distinctions in the definition are largely ignored in practical usage. Along with these three words, others like saw, maxim and apothegm could also be used interchangeably. Proverb, adage and maxim are the commonest from what I have encountered.
Solution 2:
You could say that an aphorism is a perverse or paradoxical proverb; a corrective for experience. Auden says they're an aristocratic genre of writing (Viking Book of Aphorisms). Hollingdale in his introduction to Lichtenberg Aphorims says they’re ‘philosophical,’ while epigrams are not, and they have the impact of the punch line of a joke, For example:
There are truths that go around so dressed up you would take them for lies, but which are pure truths none the less.
The world offers more correction than consolation.
God who winds up our sundials.
Georg Chrisotoph Lichtenberg
A proverb is “a short pithy saying in common use, a concise sentence, which is held to express some truth ascertained by experience or observation and familiar to all.” Shorter Oxford English Dictionary.
Webster’s Second: A proverb is an adage couched usually in homely and vividly concrete phrase; as, “accused (in the phrase of a homely proverb) of being ‘penny-wise and pound-foolish' The Spectator".
"An adage is a saying of long-established authority and universal application," Webster's Second. Shorter Oxford shows "adagial" - maybe similar to "proverbial"? and cites Lady Macbeth, 'And live a coward in thine own esteem, Letting “I dare not” wait upon “I would” Like the poor cat i’ the adage?'
An apothegm is “a terse, pointed saying embodying an important truth in a few words,” Shorter Oxford; “a terse and sententious aphorism,” Webster’s Second
Liddell & Scott say of the Greek apophthegm, “to speak one’s opinion plainly; metaphorical of vessels when struck.”
A saying "is a brief current or habitual expression of whatever form," Webster’s Second.
Solution 3:
Something I noticed reading in Wikipedia that I have not seen mentioned in your posts is that an aphorism is a an "original" statement. That alone seems to help easily distinguish it among the others. Example: Carpe diem... which is original in that we know the author of the statement was Horace from the poem Odes 23 BC. But it is short, concise, memorable, from antiquity, commonly used and understood broadly even though it is still quoted in its original language. It is formal and philosophical, yet practical. I think it could fit all the categories that we have been discussing. What do you think?