The author's hypothetical octopus "civilization" lacks most of the characteristics we associate with civilization. He seems to assume that agriculture, in the sense of pastoralism, is the only criterion. If this is the case, then ants have been running aphid-farming civilizations for millions of years. Leaf-cutter ants have run fungus farms as well.<p>I wouldn't be at all surprised that octopi and many other animals have loose farming-like behaviors. This is a far cry from what we generally mean by civilization.<p>In particular, I believe the domestication of fire is the dividing line between humans and animals. This tool provides access to an enormous new source of energy, which opened a myriad of possibilities unavailable to animals. The tool use and motor skills needed to build, maintain, and use fire probably was a significant stimulus to human brain development.<p>Cephalopods, of course, would have no opportunity to master fire.