The outermost extremities of the soul you will surely not be able to find on your course, even if you were to wander down every single path: so far-reaching is its harvest (gathering).
From this saying we can initially and generally surmise that the soul—namely, the soul of the human, who is here being addressed in regard to his course through the soul—has a λόγος: the human is a ὄν λόγον ἔχον . In this saying we hear, almost verbatim, the essential differentiation of the human that is determinative for all later metaphysics, according to which the human is ζῷον λόγον ἔχον, that (particular) living being that has a (i.e., the) λόγος . However, in the interpretation of this definition of the human, λόγος is thought as ratio—that is, as reason—in the sense of the faculty to think ideas, to make judgments based upon concepts. Now, what could be more natural than the desire to attempt to find this later, metaphysical definition of the human in the above-cited saying of Heraclitus’s? Indeed, this particular attempt to interpret the saying would have some standing and weight. However, it will not be attempted here: not because one would like to avoid interpreting the metaphysical understanding of the human essence back into the thought of Heraclitus, but rather because one still understands the word λόγος used in this saying superficially and in a metaphysical sense. For the saying speaks about the λόγος of the human soul from another perspective, insofar as it would like to express that this λόγος which the human soul has is ‘deep.’ However, one immediately refuses to think-aft er the essence of the depth of the human λόγος further. One therefore goes no further than taking this utterance of Heraclitus’s merely to be a comment on the fact that the human soul is difficult to plumb, owing to its depth. And because one already and in every case thinks ‘ λόγος’ metaphysically here, one ends up with an interpretation of this saying that  is forged by common usage. However, it is due to the uncommonness of this interpretation that we mention it here. It is uncommon because it has something to teach us.
Interpreted metaphysically and logically, λόγος means: assertion, judgment, or also ‘concept,’ insofar as one understands the concept as the coagulation of a certain comprehension, i.e., a certain judgment. Instead of using the terms assertion and judgment to describe the foundation of logical thinking, one can also just say ‘thought,’ and thereby understand λόγος to be ‘thought,’ albeit not as a thought-activity of the soul, but rather as what is thought in this activity: the thought as what gives meaning in thinking. λόγος as assertion/judgment/comprehension is thus equated with ‘concept’ and with what has been conceived (i.e., with meaning). Armed with this logical and metaphysical conception of λόγος, one can easily face the saying of Heraclitus’s and give to it an interpretation that, above all, makes immediate sense to the modern human. If we equate λόγος with concept, then with this quote Heraclitus wishes to say with his saying that the concept of the soul is so deep that all attempts to plumb its depths in
214 Logic: Heraclitus’s Doctrine of the Logos