Commentators on Maurice Blondel have often noted the similarity of his thought to existentialism. Blondel’s concept of action, for example, is remarkably similar to the concept of existence that we find in Kierkegaard, Heidegger, Jaspers, Sartre and other existentialists. Herewith, a brief comparison of action in Blondel’s L’Action (1893) with Existenz in Heidegger’s Sein und Zeit (1927) with a sidelong glance in the direction of Jean-Paul Sartre.
One doesn’t have to read much Blondel to realize that he uses ‘action’ in a broader way than is philosophically usual. Thus he does not oppose it to theory or contemplation. It includes the latter. Action in Blondel’s sense is a "synthesis of willing, knowing, and being . . . it is the precise point where the world of thought, the moral world, and the world of science converge." (Action, 40) Thus action is not the same as will when the latter is contrasted with intellect: action is at the root of both intellect and will. Action, we could say, is man’s Being, as long as we do not oppose Being to willing or knowing. (I write ‘Being’ rather than ‘being’ to mark what Heidegger calls the ontological difference between das Sein und das Seiende – but I can’t explain that now.)
So action, for Blondel, is man’s Being. As such, it is close to what Heidegger calls Existenz. Existenz is the Being of Dasein, where Dasein denotes the beings that we are. It is important to realize that Heidegger uses both Existenz and Dasein in philosophically idiosyncratic ways. Existenz is not to be confused with the scholastic existentia; the latter Heidegger refers to as Vorhandenheit (presence-at-hand). Existenz names a mode of Being that belongs to Dasein alone. As for Dasein, in ordinary philosophical German it just means existence, and contrasts with Sosein, whatness. Anything that exists, that is at hand, has Dasein as this term is ordinarily used. But for Heidegger, only we are cases of Dasein. Thus we don’t have the Being of tools (Zuhandenheit) nor the Being of naturally occurrent items like rocks (Vorhandenheit): we have a unique mode of Being that cannot be understood in terms of these other modes of Being. Thus, human beings cannot be adequately understood in Aristotelean terms as rational animals, for, on such a scheme, man is apperceived as a thing at hand in the world possessing a fixed essence.
The commentator Jean Lacroix quotes Blondel as saying, "The substance of man is action; he is what he he makes himself." (Maurice Blondel: The Man and His Philosophy, Sheed and Ward, 1968, p. 33) The substance of a thing is its essential being. So Blondel is saying that man’s essential being is action. Thus humans are not static entities with a fixed nature, but dynamic in their Being. In existentialist jargon, man is a project, a being who is essentially futural. The paradox should not be missed: man’s ‘essence’ is to lack a fixed essence.
That should remind you of Jean-Paul Sarte’s dictum that, in the case of human beings, existence precedes essence. In an artifact, something made for a purpose by an artificer, essence precedes existence: both logically and temporally the essence comes first, and then the realization of the essence. In man, however, existence comes first. But long before Sartre popularized this idea in the ‘forties, Heidegger wrote: Das ‘Wesen’ des Daseins liegt in seiner Existenz. (SZ 42) "The ‘essence’ of Dasein lies in its existence."
The scare quotes indicate that ‘essence’ is not being used in its traditional sense. Thus, Heidegger is not charitably interpreted as saying that human beings have an essence but that said essence is existence – which borders on a contradiction – but that humans beings lack an essence in the traditional sense.
Would Blondel go as far as this? I don’t know. Let’s not forget that Blondel is a traditional theist. For him, man is a creature. How is man’s creaturely status consistent – if it is consistent – with action (in Blondel’s broad sense) being man’s substance? If man "is what he makes himself," as Lacroix quotes Blondel as saying, then how can man be a creature in any traditional understanding of creaturehood? But to expound this problem requires a separate post. To be explored would be the question whether Blondel's theism is in tension with his 'existentialist' theory of action.