Not just a subject but a human being. Is this phrase a label or a description? Take its second word as a gerund, a verbal noun, then the first word is the subject belonging to that verb - as to say that this phenomenon inquiring into itself is (the) Human be-ing, as to say that its existence is act, and the kind of act in question is existential, and what expresses itself through or in that act in every single one of the multitude of instances in which it arises, is a universal subject called the Human, or pure humanness, or something more general still of which the human is an instance. Is the grammar an emanation of the metaphysics or is it the other way around (surely more likely?) that the metaphysics is an emanation of the grammar? But the tendency to think of the grammar as more basic, as say an evolved instrumentalism, begs the question of what it is that makes a grammar, any grammar possible - what is it that puts fire into a syntax so that it can get off the ground in the function of selection, of the ordering of chaos? What enables signs to signify? Say all you want against logos, something still needs to do its job. No metaphysics without grammar, fine, but look a little deeper and you'll see that there's no grammar without metaphysics. Nothing ever gets reduced (away); if you think you've done that you've only concealed what embarrasses you away into the  background. And that's what's happening here, willy nilly, no matter how much distrust you think you bring to the party.