The idea that man stands out from animals not so much because of his strengths but because of his weaknesses, i.e. a peculiar lack of natural endowments, has repeatedly appeared in the history of philosophy. However, it was the philosopher Arnold Gehlen (1904–1976) who first placed the definition of man as a deficient being at the center of an anthropological interpretation. According to Gehlen, man compensates his lack of instincts and the lack of specialization of his organic endowment with a unique "openness". Man makes a virtue out of the need of his less specific sensory and motor skills by using them to act and adapt the environment to his needs, instead of adapting himself to the environment. Man is by nature a cultural being, because his lack of natural endowment commits him to the active cultivation of his environment.