Who said "I think, therefore I doubt, and in doubt I am truly myself."?

This quote is attributed to Fernando Pessoa.

I think, therefore I doubt, and in doubt I am truly myself. - Fernando Pessoa

"I think, therefore I doubt, and in doubt I am truly myself."

Fernando Pessoa Philosophy

Poet Portuguese 1888–1935

"I am not I; I am this one walking beside me whom I do not see."

"To be great, be whole; exclude nothing, exaggerate nothing that is not you."

"The worst prison people live in is the fear of what other people think."

"I love without knowing how, or what, or even if I exist."

"I've seen the worst humanity has to offer."

"Sometimes I wonder if the world is worth saving."

"Every choice shapes our destiny."

"Order is the foundation of a good life."