Happiness and well-being
In utilitarianism, the assumed goal of ethics and morality is the greatest amount of "good" for the greatest number of people. But what counts as "good"? Evolutionary psychology tells us the answer: happiness and well-being.
Roots in Evolutionary Psychology
How do we know that this is the goal? Evolutionary psychology.
Our brains are a neural network based machine learning device designed for survival and reproduction. In machine learning, there are two mechanisms for producing a learning effect. Reinforcement, which we can say "strengthens" connections between neurons, and punishment which "weakens" them.
Our brain's reward system causes actions that result in pro-survival outcomes to be reinforced, strengthening the connections between neurons that fired to create this action and increasing the likelihood that the action will happen again. Those that result in anti-survival outcomes are weakened so the negative action will be less likely. Humans experience these effects subjectively as pleasure and pain.
It follows logically that our brains are wired to maximize behaviors that result in pleasure and minimize painful ones.
Though the evolutionary goal of this wiring is survival and reproduction, the brain itself only responds to the internal reflexive pleasure and pain reactions regardless of their actual survival benefit. Hence our goal is not to maximize our lifespans and population, it is to maximize our experience of pleasure and minimize pain.
When we live a life that gives us robust and varied sources of pleasure, while avoiding unnecessary pain and hardship, we experience this as a general sense of well-being and happiness. Therefore, the utilitarian goal of maximizing happiness and well-being for the greatest number of people can be derived logically from the observation of our brain's neural network.
We have studied the brain and determined that it's goal is to be happy.
Measuring Happiness
Yes, it is possible to obtain very useful statistical metrics regarding happiness levels within a population of people. Definitely useful enough to weigh in on utilitarian ethical questions within the legal and political systems to determine best-practices.
What If We Made Happiness the Goal?
What would be the impact on society if maximizing happiness was the primary goal and measure of our success?
Gross National Happiness is already in use in Bhutan and there is a movement to replace GDP with something similar in more countries.