He wanted to estimate N, the number of communicative civilizations out there in our galaxy, and he included in there the rate of star formation, the rate of planets, but crucially, intelligence.
彼は"私達の銀河系中で コンタクトが 可能な地球外生命体の数" Nを推定しようと 方程式に 恒星誕生の確率や 惑星の確率そして極めて重要に知性を含めました