By Greg Johnson
Years ago, a friend told me a parable about a species of hominid that did not live to inherit the earth. These hominids regarded each and every entity as entirely unique. When a tiger leaped out of the darkness and dragged one of them to his doom, this did not prompt any generalizations about tigers as a group. Thus when a new tiger began to prowl the shadows at the verge of the firelight, he was not judged on the basis of the other tiger’s behavior. Indeed, if the first tiger came back, they would not have judged him on the basis of his past behavior either, because that was then, and this is now: two unique, individual moments in time.
But even though tigers are not always man-eaters, and man-eaters are not always hungry, these poor creatures still went extinct, because their problems were not limited to tigers. They could not learn from any experiences at all. They were just too dumb to survive.
Survival, you see, requires the ability to learn from past experiences so that one can predict and even control future ones. To do this, however, one must recognize that there are not just individual beings, but kinds or types of beings. Individuals belong to the same kind if they share a common nature. And, since what we can do follows from our nature, we can infer that if a tiger is dangerous once, it will probably be dangerous again. And if one tiger is dangerous, it is probable that other tigers are dangerous too. Thus if one of us is killed by a tiger, we can take reasonable precautions to make sure that it does not happen again.
Drawing conclusions about kinds based on individuals is called inductive generalization. Induction allows you to infer that all members of a kind are “like that” based on one’s experience of individual members. These purple berries made me sick today, so they will probably make me sick tomorrow, since their nature and mine will probably not change overnight. And since you have the same nature as me, they might make you sick too. And since the purple berries on this bush are the same as the ones on the first bush, they’ll probably make us sick too. The flesh of this animal tastes good to me, so it will probably taste good to you too, since we have the same nature. And other members of its kind will probably taste good to us as well, since they have the same nature too.