Simulation

a Model, typically based on Bottom-Up Emergence from the behavior of individual actors.

Glenn Reynolds on The Sims (Will Wright)

Cosma Shalizi on Simulations, Models, and ForeCasts. It is an abuse to call every hypothesis, or theory, or mere notion, a model, just as it is an abuse to call everything from the most arbitrary detail of this year's haute couture to "linear Western rationalism" a "paradigm," or label a "system" everything in the world and a great deal more. The domain of hypotheses and theories is a great deal broader than that of models... It will be seen that hypotheses approach models, the more detailed, specific and quantitative they are. Thus Adam Smith's theory of the Invisible Hand is less of a model than Kenneth Arrow and Gerard Debreu's "General Equilibrium Model" of the economy, which itself is less of a model than Wassily Leontief's input-output models.

• Debreu suppressed Lionel Mc Kenzie's earlier work on a General Equilibrium Model. Enter a young German researcher, Till Duppe, with access to the Debreu papers, maintained at the University of California at Berkeley, where Debreu had taught for thirty years. The two met via an Internet conference and agreed to collaborate. Further details had emerged, including an astonishing fact: the anonymous referee, who bottled UP McKenzie’s submission to Econometrica for a critical time, while Arrow and Debreu tidied up their proof, was none other than Debreu himself; and Debreu hadn’t disclosed his conflict of interest to the editor, Robert Solow.