“
This distinction matters a great deal. Unlike short-term expediency, long-term self-interest, as the evolutionary biologist Robert Trivers has shown, often leads to behaviours that are indistinguishable from mutually beneficial cooperation. The reason the large fish does not eat its cleaner fish is not because of altruism but because over the long-term, the cleaner fish is more valuable to it alive than dead. The cleaner fish in turn could cheat by ignoring the ectoparasites and eating bits of the host fish’s gills instead, but its long-term future is better if the big fish becomes a repeat customer.* What keeps the relationship honest and mutually beneficial is nothing other than the prospect of repetition.
”
”
Rory Sutherland (Alchemy: The Dark Art and Curious Science of Creating Magic in Brands, Business, and Life)
“
The grouper could wait until the gobie was finished removing ectoparasites, then eat it, yet refrains from doing so.
”
”
Joseph Heath (Following the Rules: Practical Reasoning and Deontic Constraint)