“To the soul (psyche) belongs a report (logos) that increases itself.” (Kahn 101; cp. D, S 115)
“Soul possesses a logos (measure, proportion) which increases itself.” (R 115)
The authenticity of this fragment is often questioned. It comes from John Stobaeus, who mistakenly attributes it to Socrates. However, given that the statement in Stobaeus previous to this one is attributed to Heraclitus and it has similarities to the reference to logos in Fragment 35 (D, R, S, F45), the fragment has long been thought to stem from Heraclitus.
Logos has often been translated by Kahn as “account” but the term is also often translated as “measure” of “proportion.” The sense here is that the individual soul is not a contained and finished entity but an expansive one. The passage is often read together with the earlier noted F 35: “You will not find out the limits of the soul by going, even if you travel over every way, so deep is its report.” Though Heraclitus is not thought to have the idea of an immaterial soul, he does indicate a view of an expansive one. In contrast to the elements of the world which are recycled from fire to earth, air, and water, earth, but remain of a constant mass, the soul increases.
We might today simply say it is of the nature of humankind to always learn — collectively and individually. In Robinson’s offered paraphrase, “measured increase is a mark of the soul” (p. 157). Robinson underlines that Heraclitus has a physicalist view of the soul, and indeed of everything.