What does the poem The Smile by William Blake really mean?

There is no poet who has delved so deeply and critically into human nature and society, questioning our presuppositions and evoking a sense of the uncanny, like William Blake. "The Smile" says in four stanzas what 1000 philosophers could not say in 1000 books. This poem reflects the two-fold nature of human existence, as well as the duality between appearance and reality, by simultaneously revealing and concealing its inner meaning. Behind the finite interpersonal meanings of smiles and frowns, which ought not to mislead us about the totality comprised of positive and negative moments, there is a whole other layer of significance. The smile of smiles, whose inner nature is invisible, can only function in the finite world by means of potentially deceptive appearances, either as love or deceit depending on the character of the recipient. The frown of frowns-bitter experience beyond merely personal discord- induces radical self-doubt, which can only be relieved by an equally cosmic smile which surmounts the traps of the finite and restores the self. Thus Blake, by smiling upon my hungry consciousness with his intelligence as no one else can, fills me up with indescribable joy and helps me to surmount all disappointments.