“The first step is to look around at the rich fabric of the phenomena around us. Next, we selectively ignore nearly everything about these phenomena, snipping the fabric down to just a few threads. This process involves (a) selecting a simplified but real model system for detailed study and (b) representing the simple system by an equally simple mathematical model, with as few independent constructs and relations as possible. […] The last step is to (c) deduce from the mathematical model some nonobvious quantitative, and experimentally testable predictions. If a model makes many such successful predictions, we gain conviction that we have found the few key ingredients in our simplifying steps (a) and (b).” Philip Nelson, p. 16-17 (2004).

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