This is a quote from the book "The Virtue Of Selfishness" by Ayn Rand
...of such bromides as “Nobody is perfect in this world” — i.e., everybody is a mixture of good and evil, and, therefore, morally “gray.” Since the majority of those one meets are likely
to fit that description, people accept it as some sort of natural fact, without further thought. They forget that morality deals only with issues open to man’s choice (i.e., to his free will)
— and, therefore, that no statistical generalizations are valid in this matter.
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If man is “gray” by nature, no moral concepts are applicable to him, including “grayness,”...