To construct a discourse it is necessary to start from a thesis. Finding arguments, evidence, reasoning, a coherent vocabulary, affirmation and refutation devices. A discourse presupposes a conscience, a subjectivity that draws sums. And a unitary design.
In contrast, the aphorism suspends shared rules and coherent principles. Sometimes it forces its author's hand, leading him to camouflage himself, if not to contradict himself.
At other times it has the air of being a verbal oversight, a grammatical error, a typo, a communication disturbance, a Freudian slip, a nonsense.
In one place a vowel falls, in another a consonant intrudes. Here a word replaces another that acoustically resembles it. There, it is a prefix that you do not expect that gives the sentence a different meaning. And it all happens in a handful of words, in the space of a line or two, in a fraction of a second. Like a flash of lightning, a thunderbolt rushing across the page or your mouth.
As de Saussure put it, the aphorism takes the langue and, with words, does what it wants with them. It uses the codified and handed-down collective heritage to elaborate its own transgressions with discreet independence.
Reality and words, two worlds that normally correspond, thus move away from each other. And fortunately so, because one is bound to the demands of necessity and logic, and the other to those of imagination and combinatorial art.