What is the difference between sum and existo?

1. What is the difference between ergo and igitur?
2. What are the variations of cogito ergo sum?

What is the difference between ergo and igitur?

Both “igitur” and “ergo” can be used interchangeably, they do indeed mean the same thing so technically it would be correct to say “ cogito igitur sum”. However there is a preference towards using “cogito ergo sum” simply because this is a quote and it is the way Descartes chose to form his sentence.

What are the variations of cogito ergo sum?

However, the Latin version from Principia Philosophiae — “Cogito ergo sum” — is better known. The French and Latin versions of the quote have traditionally been translated in English as “I think, therefore I am.” Alternate translations include “I am thinking, therefore I am” and “I am thinking, therefore I exist.”