Pessoa’s scepticism is not greatly different in its view of the limits of human reason from the sceptical philosophy developed in the ancient world by Pyrrho and Sextus Empiricus, versions of which have been revived in modern times not only by Montaigne but also by David Hume.
Where Pessoa differs from most exponents of systematic doubt is in his intent, which was not to prove the validity of scepticism or even – like Hume, in some moods – to encourage people to give up philosophising and return to everyday life. If Pessoa’s philosophical writings had any overall purpose, it was simply to emancipate the mind and enlarge the imagination. The human value of philosophy was not in underwriting any view of things but in making possible a certain kind of mental freedom.
Source: John Gray, Reviewed: Philosophical Essays – a Critical Edition by Fernando Pessoa