I was thinking about this a little bit last night, after being impressed with your previous post: "How can limits be introduced, and still have the metaphor applicable?"

I've read a lot of Gould, and I've learned about constraints. At the molecular level, whatever the chemistry cannot do is a constraint. At the level of individual members of the species, there are biomedical constraints on the ways, and extents to which, internal organs and external structures can vary and still result in a viable organism. At the community level (pack, flock, pride, school, or other small group) the environment takes over, providing constraints on the instinctual behaviors of individuals and groups that still allow the survival of succeeding generations (this is the stage upon which Darwin observed and defined natural selection, of course). The larger the group considered -- ultimately, the total populaton of a species -- the larger the scale at which environmental constraints operate, in time as well as space; for instance: geographical isolation (and occasionaly its removal via plate tectonics), climate change, and Malthusian population pressures on resources.

The salient difference between a process like evolution and a process like economics is that, in the latter case, the environment is social as well as physical. Further constraints are imposed by human psychology, in the individual and in the aggregate.

I'm beginning to conclude that there is something in the human mind that is allergic to the concept of "spontaneous order," of things working out for the best...

I think you may be right. I disagree, however, with this:

I wonder if the psychological reason people can't accept a free society without a "controller" making sure everything works, is the same reason other people can't accept the idea of a universe of this complexity without a "Watchmaker."

I would propose instead that one important and necessary social constraint on the evolution of an economy stems from a necessary psychological survival trait evolved by the human species: compassion. I say this because (without being versed in economic history per se) the social constraints placed upon modern "nearly-free-market" capitalism in the last century and a half have had their origin in societal concerns for the participants. In other words: "things working out for the best" is not defined exclusively by the economic entities themselves, but also by the psychological environment in which they operate.

To keep this particular post from becoming too long, I'll choose one simplisitc example: Monopoly. Anti-trust legislation was formulated to check the unlimited growth of certain 'organisms' within the economic species, owing to the effect that growth had on individual humans (and groups thereof), as well as on competing economic entities. [Obviously, the economic system itself contained no such constraint, or monopoly would have been impossible.] Bringing it back to the evolutionary metaphor: A change in the environment limited the size of gorillas to 500 pounds.

A similar case can be made for child-labor laws, as representative of an entire class of constraints on the internal workings of economic 'organisms' -- analogous to the level of organs and structures within a biological individual (see above).

Finally: I believe it was a deliberate disregard of the psychological environment in which all economic systems must live and evolve -- specifically (but not exclusively) the constraint of compassion -- which led to the Darwinian demise of Soviet-style communism, by inducing its internal organs (its people, as well as its processes) to cease cooperating.