The parvis is a very broad comparison, (I-.-II-.-III-.-IV), having something in common with many other figures of speech, in particular the tartan. Represented diagrammatically it resembles the overlap (E-/F-/H-/R) but its contents can be repeated or multiple, as in (A-.-E-.-E-.-FH). The meaning is still “I is to II as III to IV” but in a loose way in which the elements may be materially but not explicitly present. Similarly it is not necessary for the parvis to mix mutually foreign notions as in the most plausible tartans. This makes (Archimedes-.-genius-.-you-.-talent) possible, from “you are an Archimedes” to express strikingly “as Archimedes was a genius, you have talent” [333].
The parvis shows the continuity linking the tartans and many distinct turns of phrase, so that once again Leibniz was justified when he wrote [499]: «Nothing is done all at once…» The mind seems to take what it already knows and, by extension, create a sort of metaphor to conceive of the new, based on the old [523]. In certain cases there is no replacement word, as in “the down of planks” which we can use to describe the minuscule excrescences on a newly sawn plank of wood [308]-[803]. The metaphor occurs when there is a substitute word, such as in “the summit of the building” describing “the roof of the building” and this requires a perception of a relationship between different objects [36]-[345]-[804].
The uncertainty often sought after in art, in particular the mixing up of different sensations, is considered elsewhere as harmful to clear and reasonable thought, leading Descartes to comment on metaphysical things [267]: «…those who want to use their imagination to understand them, do so as if, to hear sounds or smell odours, they were trying to use their eyes…»