A thought experiment to refute psychological egoism
There are two kinds of egoism--psychological egoism, and philosophical egoism. Psychological egoism is a descriptive theory, and philosophical egoism is a prescriptive theory. Psychological egoism describes how people act, and philosophical egoism prescribes how people ought to act. With that explanation out of the way, let's move on.
Psychological egoism is the theory that everything we do, every choice we make, every act of the will that is ours, is motivated primarily out of what we take to be in our self-interest. Altruist acts are impossible. Even acts that appear to be altruistic turn out to be self-interested when examined more closely.
Psychological egoism is hard to refute, because once you start throwing out a few counter-examples and see how the psychological egoist goes about proving it to be a self-interested act, you begin to see the pattern, and you realize it's not going to be easy to come up with a counter-example.
A couple of years ago I read a scenario on the internet that was supposed to serve as a counter-example to psychological egoism, and I'm going to share it to the best of my memory. I'd give credit to the person who came up with it, but I don't remember who it was. This scenario is a thought experiment. It's just a hypothetical scenario that allows us to think carefully about this issue.
In this scenario, a man buys a life insurance policy for his family to take care of them when he dies. The life insurance policy costs him $25 every month. An ordinary person would say that in choosing to get the life insurance policy, this man is not acting in self-interest. He gets nothing out of the insurance policy since it doesn't pay until after he's dead. Moreover, he has to pay $25 a month for something he gets no benefit from.
The psychological egoist, however, will argue that he's acting in self interest. This man loves his family and can't bear the thought of them being high and dry if he were to die all of a sudden. He gets the life insurance policy for his own psychological well-being. It gives him a feeling of comfort, knowing that his family will be taken care of. So getting the life insurance policy is an act of self-interest.
Let's concede the point. The man would get psychological comfort if he gets the life insurance policy. But let's say there's a pill he can take that will give him that exact same psychological feeling of comfort, but without having to pay $25 a month for a life insurance policy. Clearly, it would be in his self interest to take the pill instead of getting the policy. Let's look at the two choices and compare their self-interested pros and cons.
Life insurance policy:
Psychological feeling of comfort.
Have to pay $25 a month.
Psychological feeling of comfort.
Get to save $25 a month.
Since the life insurance policy doesn't benefit the man at all, the only possible benefit he could get is psychological. But if there's a free pill that can give him the exact same feeling of comfort, then it's clearly in his self-interest to take the pill instead of getting the life insurance policy.
The question is, what choice would any ordinary man make? If given the choice, most people would choose the insurance policy. That proves that psychological egoism is false.
The real motivation for getting a life insurance policy is not the psychological benefit a person would get from it. True, they would have some psychological benefit, but that benefit is the result, not the cause, of their choice. That's one of the problems with the way psychological egoists argue. They confuse results for causes. The real motivation for getting a life insurance policy is the well-being of our families after we're dead. We are motivated by their interest, not our own.