Positive Psychology is a relatively new branch of traditional psychology, and its main tenant is that the absence of disease is not health. Someone who doesn’t have any diseases but doesn’t excersize or eat well may not be sick, but they’re not very healthy either. I just posted about this, Do you just want to not be sick?.
The reason it might become the next most important science is because it is concerned with improving the lives of normal human beings, not just fixing the ones that have problems. As human life expectancies increase (at the rate of almost a year, every year), we will have more and more time, the quality of that life will become important. Someone who’s been stuck one way, in a unfulfilling career, putting off finding some meaningful work until “tomorrow” may do that for 100 years rather than just 40 years. And that’s just a waste.
I applaud this Positive Psychology movement, because there’s a number of things science and the scientific method does well, and creating reams of data and testing a whole bunch of things. In contrast to the more market-driven personal development field, you’re more likely to get accurate data of what works for how many people. However, as always, some things just don’t work for some people, but some things which have great effects might work for you, so the process of experimentation and testing will never be entirely removed from individual responsibility.
This movement has already produced some magnificent work. The concept of learned helplessness, by Martin Seligman. The concept of flow, by Mihaly Chezhmihaly. Peak experiences, and the hierarchy of needs by Abraham Maslow. Non-drug treatments for depression, and so on. This is important stuff and will become ever more important going forward.
Nick Bostrom recognizes this in a very important talk at TED, called “Humanity’s Greatest Problems aren’t what you think“.