"A definition? That a substantial amount of speciation occurred during (geologically) relatively short periods of time, between which were long periods of relative stasis without actual speciation, although gradual changes were always occurring."

Mr. Rosser, This definition is very much like that in Wikipedia, true. As stated, it follows directly from observed adaptive radiation -- which has had explanations involving genetic drift. There is nothing new in this definition. It is not a new observation. Tnere is no new idea expressed here beyond the old observation. This is a pretty shiny packaged christmas present with nothing in it.

Can you state a definition that shows what's special about punctuated equilibrium? If you can't, then there's no reason to think you understand it.

I looked at your economics homepage. I think you're studying a fascinating specialty and I wouldn't be at all surprised if I learn interesting and useful things as I read your publications. Thank you for the link.