Seligman basically says nothing about meaning (but Wikipedia’s Meaning of life is an excellent overview). Engagement is effectively synonymous with flow/wu wei. Pleasure is 50% heritable (which explains why winning the lottery doesn’t make you much happier in the long run) but the other 50% can be changed.
Seligman has both academic and commercial sites with a bunch of questionnaires. The only intervention he talks about for engagement is to restructure unengaging tasks to focus on “character strengths” (although there are others). To increase pleasure there are at least two effective engagements:
- gratitude training (eg: a “good times” journal, writing letters of gratitude)
Mindfulness is supposedly based on Buddhist meditation, but I think there’s some confusion. As I see it, Buddhist meditation includes two kinds of mindfulness:
- awareness of the present moment external to the self
- meta-consciousness: observing the structure of the self (the “monkey mind”) to transcend the present
The purpose of awareness training in psychology is to increase the pleasure gained and retained from pleasant experiences. When the sense of self is removed to savor an experience, you increase pleasure. When the sense of self is removed in carrying out a task, you increasing engagement. There is a correlation between these but I don’t think positive psychology understands the causal relationship yet.