Since the human mind has limits and time is the eternal constraint, the use of situational ethics can easily degenerate into a moral quagmire that binds you into modes of thought that subtly or severely limit your potential. Conversely, they can splinter your personality into fragments that destroy your cohesive identity.
One solution is to use the same ethics for all situations. This solution is ideal in theory, but leaves you vulnerable to people or situations that conflict with a belief in absolute ethics. For example, if you believe guns are bad, you make yourself vulnerable to criminals with guns who don’t care about your beliefs. If your family is starving to death and you can’t grow or buy food, then stealing from rich people who have too much food (à la Robin Hood) might be a better solution than just giving up and dying. Similarly, if you meet your soul-mate while in a bad marriage, the best choice for your happiness may be a divorce or an open marriage. Absolute ethics may work on paper, but not in real life, because people and situations change. If you live 80 years, that’s only 22,645 days as an adult, so it’s important to make every day count. However, it’s good to have firm guidelines that you only violate in extreme situations.
Another solution is to use ethics that maximize your personal happiness. Doing this in the short term could involve eating lots of chocolate and ice cream, but for true happiness, you should eat a balanced diet that’s good for your body, mind, and spirit. Doing this is not delaying happiness, but extending it over a long range of time and variety of mental states. If you maximize your personal happiness, you might take advantage of other people, but then when that stops working, you’ll be nice to them to get what you want. You may also choose to do unto others as you would have them do unto you. If you choose to believe in Jesus, Allah, Buddha, or all of them, you do that for yourself and your eternal soul rather than social, family, or peer pressure.
A third solution is to use ethics that maximize humanity’s happiness. While this can obviously be combined with the previous, they are generally at crossed purposes because what’s good for someone else is often not good for you. For example, it might make a stranger happy if I gave them my digital camera, but I would prefer to keep it because I bought it, I own it, and it’s my property.
A fourth solution is to use ethics that maximize your family’s happiness. I like this option best, because I honestly can’t care about all the people in the world or myself alone. Many people are mean and inconsiderate, so it’s important to pick your family closely, and it does not necessarily have to be your blood relatives, but you should not disown them.
Of course, you could also choose to cause as much chaos, death, destruction, and suffering in the world as possible, but this is degenerative and any benefits to this approach are side effects, so it is ultimately corrupt. Nazi Germany used this approach in the Holocaust, as did the United States by nuking Japan and defoliating Vietnam. This leads you down the path of fear, and makes you believe that no one is worthy of trust, which is a very lonely, dis-empowering, and depressing belief.
Traditionally, situational ethics are the domain of the right brain and concrete ethics are the domain of the left brain, but this is a stereotype and like all stereotypes, it is often wrong. You can define your own reality within the constraints life has given you, and you can change your reality to a fault, usually bounded by time and ingenuity.
In general, I would recommend not adopting the mental framework of situational ethics, because it leads to treating other people like objects rather than sovereign humans. It’s better to develop a good sense of intuition to implicitly judge people, while always giving the benefit of the doubt. Finally, it’s important to recognize that words are always less important than actions and that what you see in others is always reflected in yourself, so be careful.