Moral values evolve to preserve individuals and species. They evolve through intricate methods that have been debatable among many biologists until our current day. Regardless of how they evolve though, it’s the consensus that moral systems are there because they help the species. It is impossible for an ethical value to be predominant in a society without serving a purpose at the time when its most popular. Some ethical values however lose their function over time and it takes a few generations after that to repeal them; which explains the existence of moral systems that are not useful at times.
Incest is a practice that has been not unpopular in lots of cultures in history, notably the pharaohs in ancient Egypt. Incest, although still practiced at individual levels, is predominantly unacceptable in any culture on Earth at the current time being. Because of the undesirable effects that incest brings on to offspring, moral systems evolved to repeal it. The systems worked at first perhaps by criminalising it and very gradually did these systems start getting engrained in the public psyche. People not only avoided it but developed genuine feelings of disgust and revulsion of the actual practice. It is argued that this feeling of disgust has become so profound that it is actually ingrained in our own DNA by now. Although the vast majority of people are revolted of the practice of incest per se, laws banning it continue to exist against it although being virtually useless now.
As climate change is becoming a pertinent issue that is threatening our entire existence, moral practices will start to evolve to counter these threats. Vegetarianism and Veganism are on the rise whilst scientists are warning of the huge impact of cultivating farm animals and cattle upon our atmosphere. Meat eating is starting to become, like never before, an immoral practice to relatively large sections of western societies. The trajectory that meat eating is taking is similar to the one incest took many thousands of years ago. It starts to become unacceptable amongst a class of people who are thought by the general public to be radical, and whilst this class of people grows, laws banning the practice will start becoming effective and gradually people will start developing feelings of disgust and revulsion of meat eating. It is important to notice that the reasons that compels people to be vegetarian and revolt them from meat eating, such as compassion with animals, are not necessarily the reasons vegetarianism is useful; and are not the reasons these feelings have evolved. It simply is a dirty trick created by the human mind to achieve a selfish human need.
Eating meat in 1000 years from now might a have a similar status to incest. Extremely disgusting and repulsive but yet with laws banning it despite the fact that the majority of the public don’t need these laws to stop them from eating it at the first place.