what it is, as the no-longer-sayable and the no-longer-utterable, owing to its relation to asserting. However, λόγος does seem to be constituted differently than ἦθος. Asserting can perhaps relate itself to all beings; but asserting, taken strictly for itself, is only a particular and isolated activity among the totality of activities that comprise the bearing of the human sojourn amidst beings. Seen from this perspective, λόγος is only a special case among the other possible human activities.
λόγος, as the activity of asserting, belongs to ἦθος, which is the bearing that pervades all behavior. Hence ethics, as the knowledge of human behavior in relation to this bearing, is the more expansive knowledge that includes logic within itself. ‘Logic’ is, as it were, a particular kind of ethics, that of assertoric behavior: logic is the ethics of λόγος, the ethics of asserting. If this is the case, then any justification for equating logic with the other forms of knowledge (i.e., physics and ethics), or even placing it above them, falls away. The human, insofar as he is seen and thought with regard to his universal relations and modes of behavior  toward beings as a whole, is determined by ἦθος . That is why we would be justified in saying that the human is that particular being amidst beings as a whole whose essence is characterized by ἦθος .
However, in light of the form of the human essence just now delineated, we come upon something strange: namely, that in the Greek world, and throughout the entirety of Occidental history following upon it, the human is defined as τὸ ζῷον λόγον ἔχον, that living being who has as its defining characteristic both saying and asserting. This determination of the human essence with an eye toward λόγος gets its character through the differentiation of the human from the animal, and thereby within the context of the life of living beings in general. The animal is, with respect to λόγος, ζῷον ἄλογον, the living being without λόγος . However, α - (i.e., “without”) does not mean here an absence, a lack, and a going-without. Indeed, going-without is only present where the absent as such has become recognizable through a desire for it. The animal is entirely excluded from λόγος, no matter how ‘intelligent’ animals may be (and no matter how eager modern psychology is, in a strange misapprehension of the simplest connections, to research the ‘intelligence’ of animals). The human is characterized by λόγος: it is the human’s most essential possession.
Following what was elucidated above, one might rather expect a characterization of the human essence that reads thusly: ἄνθρωπος ζῷον ἦθος ἔχον, the human is that living being whose ownmost and most distinguishing characteristic is ἦθος . However, instead of this, λόγος is now seen to have the undeniable primacy over ἦθος . The essence of the Occidental human finds itself being imprinted upon by the character of ζῷον λόγον ἔχον . The Roman re-articulation of this—which is something more than just a translation into Latin—reads: homo est animal rationale, the human is the rational living being. If we pay attention to the relation of ratio and λόγος to thinking, and the equating of both, then we could also say:  the human is the thinking animal. If we understand thinking to be the form
164 Logic: Heraclitus’s Doctrine of the Logos