This is a quote from the book "The ​Virtue Of Selfishness" by Ayn Rand
...e can objectively be taken to mean agreement with or sanction of evil. When one deals with irrational persons, where argument is futile, a mere “I don’t agree with you” is sufficient to ne gate any implication of moral sanction. When one deals with better people, a full statement of one’s views may be morally required. But in no case and in no situation may one permit one’s ow n values to be attacked or denounced, and keep silent.

Moral values are the motive power of a man’s actions. By pronouncing moral judgment, one protects the clarity of one’s ow...
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