The quote this week:
Just as the alchemist yearned for a formula that would turn lead into gold, so the modern biologist longs for a conceptual framework that will make any data set coruscate with revelations. The framework described here falls considerably short of such expectations, but then, modern chemistry has not fulfilled the alchemists’ most ardent dreams.
S. J. Arnold (1983, p. 357).
From the following paper:
J. G. Kingsolver and R. B. Huey (2003). Introduction: The Evolution of Morphology, Performance, and Fitness. Integr. Comp. Biol. 43 (3): 361-366. doi: 10.1093/icb/43.3.361
is also the introduction from a special issue covering many interesting aspects of measuring natural selection. Seems like it is mostly open access, so I can link for you to go & pick on these various examples.
Then we can discuss the relevance of introducing path analyses to the study of natural selection in the wild: was it gold? I’d tend to think it was.