Emergence means various things to various people, but the basic idea is that complex behavior can emerge from simple rules or physical laws when there's enough of these simple processes running in parallel and interacting, and that even the general form of this complex behavior is not at all obvious from examination of the rules. For example, from atomic physics emerges chemistry emerges life emerges mind emerges culture. Another characteristic of emergence is that order emerges out of chaos, which thermodynamically requires an energy input.

This much is not in dispute. The question is what does it mean? In particular, what does it mean for the reductionistic approach to developing scientific theory and insight? Is all of science a big mistake, and do we need a new holistic theory of everything?

Our take on this issue is that:

• Reductionistic explanations clearly have great power, and are by no means wrong, but their power is limited by emergence.
• It is also fruitful to develop sciences of complexity such as biology, psychology and sociology/anthropology, but results inevitably become messier and more tentative, soft science.
• It is a grievous error to say that a lower-level explanation is “more real” than the higher-level phenomenon that it explains.

It is intuitive, and seems to be a human cognitive bias, that when anything has been explained (even wrongly so), that the explained phenomenon becomes less significant and less real than the explanation. Although this approach is the cause for and justification of theory-building, and seems to serve us well in daily life, it has become troublesome as we understand the world at ever-finer levels of detail.

This problem is particularly clear in Evolutionary Psychology and the reactions to it. As we start to understand human motivations and feelings as unconsciously pursuing reproductive success, we explain, and therefor seem to demean something which is extremely real to us. Is love real or not? Love is real, but it predictably appears in particular ways which are well explained as strategies for pursuing reproductive success.