In this way, of course, Pessoa is doing his own rendition of one of the key questions in the European philosophical tradition, this question of being estranged from “being,” a question that begins with the likes of Spinoza and Schopenhauer, and continues right up through Heidegger and Sartre (of course), and which is a major concern of French post-structuralists like Barthes, Derrida, and Lacan. To me, this impossible desire informs much of that saudade that one finds endlessly throughout Pessoa, this omnipresent sense of one’s own estrangement, and this wish that one might be like Caeiro and enter into a sort of pre-linguistic relationship with the world — this complete absence of all artifice would yield the most beautiful poetry possible.It's a pity Pessoa's Textos Filosóficos aren't more readily available. He wrote them in English. They're in the public domain. Google Books only has a recently copyrighted (text not shown) Portuguese translation.