"The test of a first-rate intelligence," F. Scott Fitzgerald once wrote, "is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function." It's time for greens to co-opt corporations. Photo: iStockphoto If so, then the growth of the green economy -- embraced by corporations, heralded by politicians -- marks something of an IQ test for the progressive movement. How can we at once celebrate companies that move toward better practices while acknowledging how much farther they need to go? The signs of change are everywhere. General Electric and BP …