As I have written several years ago, human intelligence can be defined with good precision: it is high enough to fatally damage its natural habitat, but too low to repair the damage (“To Repair the Damage,” September 21, 2007). A few qualifications are needed at this juncture, though. First, I assumed that the entire planet was the species’ natural habitat. Second, I assumed that the species was incapable of moving to another planet once its natural habitat was damaged past repair. Further qualifications like the above might be needed, of course. Even though the species cannot do anything about it, every step toward a definition of human intelligence is of value. At least it offers a clear vision of the future.

Addendum (March 6, 2016)

Come to think of it, a species capable of moving to another planet once its natural habitat was damaged past repair could in time learn how to hop from planet to planet. As soon as a planet’s natural habitat was ruined, it would look for another one. Hopping across the universe in search of planets capable of sustaining it, the species could live forever. That is, as long as the universe itself. All this is reminiscent of early agriculture, when small groups of humans moved from one fertile area to another, never staying at any one area for more than several years. Planets could serve an intelligent species in the same way, albeit for longer periods of time. In short, my definition of human intelligence is rather narrow, but it still serves its purpose in this particular case. Hoping planets is well beyond human ken now or ever.