Use of metrics to refine techniques and improve results. "After Apgar, obstetricians decided that they needed a simpler, more predictable way to intervene when a laboring mother ran into trouble. They found it in the Cesarean section."

Turing proposed that the activator would form something like a tiger's stripe, but then interaction with the inhibitor would shut down its expression, creating a blank space. Then the process would reverse, and the next stripe would form. The interaction of these two morphogens would combine to create the full stripe pattern.

But what’s striking about the commission’s report, read from a 21st-century perspective, is how limited our own debate about inequality seems by comparison. For the commission, inequality was a fundamental problem that threatened the entire fabric of American democracy. Today, by contrast, we’re busy debating whether a multimillionaire like Mitt Romney ought to pay a few more percentage points in federal taxes.

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