Substitution Cipher Puzzle

This phrase, originally "Cogito, ergo sum" in Latin, was first published by French philosopher Rene Descartes in his 1637 work "Discourse on the Method." Descartes arrived at this conclusion after systematically doubting everything he could, finding that the very act of doubting proved the existence of a thinking mind.

The statement became the foundational element of Western rationalist philosophy. Descartes argued that while our senses can deceive us and our beliefs may be wrong, the fact that we are thinking at all is undeniable proof of our existence. This simple yet revolutionary insight shifted philosophy toward the primacy of individual consciousness.