Because in agriculture, if you had 10 kids and you grow up a little bit earlier and you work a little bit harder, you could produce about five times more wealth, on average, than your neighbor.
農業では子供が10人いて 少し早く生まれて 少し多く働けば 平均的に 隣人と比較して平均５倍程度の 富を生み出せます