Appeal to nature
An appeal to nature is a logical fallacy by which it is argued that because something is "natural" it is automatically morally desirable or "good". Sometimes the argument appears in reverse form: that because something is not found "in nature", it must be morally repugnant or evil.
- Everybody should eat meat, because humans evolved to eat meat.
- Homosexuality is not natural; therefore it is wrong to be homosexual.