When Heraclitus states that individuals have their own understandings even if through their being they are in fact participating in divine logos, which operates on a cosmic scale, Heidegger, as a keen reader of the elusive sayings of this pre-Socratic philosopher of Ephesus, must have found a genuine affinity with his own reflections on the meaning of being (Sein). Translated into the terminology of fundamental ontology in Being and time, Heraclitus is effectively saying that the understanding of being (Seinsverständnis), which is essential to the phenomenon of understanding, can only take place as Dasein. Beyond Dasein, being (Sein) becomes the ineffable and cannot be understood. Perplexity takes the place of understanding; perhaps also awe; and wonder. Dasein, in its authenticity, is circumspect about its own finitude – which is temporalised as being-towards-death (Sein zum Tode).
Heraclitus goes as far as saying that there is no difference between life and death, for both are but transmutations of the one and the all. In metaphysics, the all-encompassing is being (Sein) itself. Being is being, but gathers different beings (Seiende): as Heraclitus puts it, the name of the river is the same, but its water is not. Heidegger’s discovery of the ontic-ontological distinction in his notion of the ontological difference in Being and time is essentially founded upon a Heraclitean inspiration.