The best known philosophical statement by René Descartes is "Cogito ergo sum" (French: Je pense, donc je suis; English: I think, therefore I am).
COGITO = ERGO * SUM
Which digit does each letter represent? (Please present the full analysis how these digits can be determined. Every letter stands for a digit in base-10 representation, different letters stand for different digits, and leading digits are always non-zero.)