Final answer:
An act can come to be viewed as unethical from perspectives of deontology, utilitarianism, virtue ethics, or cultural relativism; depending on rule adherence, consequences, character virtues, or societal norms.
Step-by-step explanation:
Through time, an act can come to be viewed as unethical under various philosophical perspectives such as deontology, utilitarianism, virtue ethics, and cultural relativism. Deontology bases the ethicality of actions on adherence to duties or rules, suggesting an act becomes unethical if it goes against these duties. Utilitarianism, being a form of consequentialism, considers an act unethical if it no longer contributes to the greatest good or general welfare. Virtue ethics, concentrated on character, would deem an act unethical if it reflects poor character or virtues. Cultural relativism views an act as unethical based on a change in a society's norms and values, asserting that morality is society-specific and can evolve over time.