His idea of soft inheritance was a reflection of the folk wisdom of the time, accepted by many natural historians. Lamarck's contribution to evolutionary theory was an early, perhaps the first, theory of evolution. In Lamarck's theory, an alchemical complexifying force drove organisms up a ladder of complexity. A second environmental force adapted them to local environments through "use and disuse" of characteristics, making them different from other organisms. Since these ideas cannot be reconciled with what we know about genetics, they are now history.