René Descartes' saying "Cogito ergo sum" has been widely spread all over the world. In English it is commonly known as "I think therefore I am", but it is also known to us that "therefore" is not a conjunction, and thus the proper sentence should be "I think. Therefore I am" , "I think; therefore I am" or even "I think, and therefore I am".
Regardless of that, I wonder if "I think therefore I am" is not grammatically correct, then how can it be accepted by the whole English world?
Hence how to figure it out?
I would write it "I think, therefore I am." and I have also seen it written that way by others.
As to the "I think therefore I am." punctuation, I'm guessing that if it's commonly written that way, then it was considered acceptable punctuation at the time it was translated from Latin. And then people have just got used to it being written that way.
I've always seen it rendered in English with a comma after think, as "I think, therefore I am."
Checking: my rather old print copy of "The Oxford Dictionary Quotations" presents it as "Cogito, ergo sum" and then translates it as "I think, therefore I am."
Wikipedia has an entire article on "Cogito ergo sum" (no comma) at https://en.wikipedia.org/wiki/Cogito_ergo_sum . It opens:
"Cogito ergo sum is a Latin philosophical proposition by René Descartes, usually translated into English as 'I think, therefore I am'. The phrase originally appeared in French as je pense, donc je suis in his Discourse on the Method..."
It never occurred to me that it was originally written in French, not Latin.
