Cogito ergo sum.
According to generally accepted "rules" of cassical Latin composition, generally speaking, the main verb would be the last word in the sequence. Consequently, the main verb according to this approach would be the "sum" = I am.
If this statement "cogito ergo sum" was composed according to the classical "rule", it would translate thus:
I am, therefore I think.
Which puts an entirely different spin on the whole issue. And wouldn't it be logically tenable that "to be" had to come before the capacity to think could exist?
To be, or not to be.
To think, or not to think.