by Tom McBride


Tom McBride 

Professor John Passmore explains David Hume’s theory of induction with the following story. A small child is always given a nice gift of soft furry toys, such as teddy bears and little baby elephants. He sometimes drop them, and they land with an almost inaudible sound. Then one day the lad is given a rubber ball instead of a soft,, wooly, stuffed thing. He drops the rubber ball, and to his astonishment, it bounces up

     He is gobsmacked. According to Hume, he could not have predicted this bounce because he had never had any experience of rubber balls before, and according to Hume as well,we gain knowledge of things only through sensory experience. After a while, of course, after we have seen x number of rubber balls do their bounce, we come to expect that they will do so and may even imagine that we knew all along that they would bounce, even before we had seen one do so.  Hume says this is a mistake, since we could not know in advance what the rubber ball would do until we had seen it with our own eyes. We have no prior knowledge of the bounce, but we can reasonably expect that a rubber ball will bounce over and over again. It always has, after all. 

     We can predict based on previous experience that it will bounce over and over, but then one day it might not. Our process of induction is fallible, as with the famous, related business of the swan, which we know is always going to be white until we go to Australia and see some that are black. So we have no prior knowledge, and our predictions based on prior experience, whether with rubber balls or black swans, is unreliable. Hume would eliminate a a priori knowledge and establishes the poverty of induction in one fell swoop. We might even say with one lethal bounce. 

     Let us try another thought experiment with this same child who is amazed when her ball bounces and does not land with an unheard sound as when

 she drops her teddy bear. Suppose you told her that someday, maybe soon, the Earth would get too hot and would gradually burn up. The icebergs would melt and farm land would become a desert. It’s a scary story. Would she believe you? Well, remember: she has had relatively few days upon the Earth, and much is brand new to her. If a ball can bounce—surprise, surprise—then the Earth could surely heat up with a lot of destruction. This could be a way of saying that kids are innocent and gullible, but it might also be a way of saying that kids, who have not had thousands and thousands of days in which most things have not changed—where rubber balls always bounce and most swans are white, and where there’s always plenty of oil and gas to keep the lights on and where you can still swim off the shore of Miami—would be more open to something astounding turning out to be true. We adults, on the other hand, are a little bit like the two guys who fall off a one hundred story building. One says to the other, “Well, we’ve fallen twenty-five floors without anything bad happening to us, so I suspect we’ll be OK.” Nothing better illustrates the motivating power, intellectual poverty, and utter complacency of induction. 

     Induction is a trap and a dilemma. We would be unable to negotiate with existence if we did not take many things for granted—our house will still be there when we wake up in the morning and our jobs will be waiting for us when we arrive at work—but nothing more stifles the imagination of either happy or dreadful possibility like tried and true—but really untrue—induction.. It prevents us both from thinking outside the box and anticipating dire possibility. 

     This is why the child with the rubber ball or stuffed baby elephant is more open to the possible destructiveness of climate change than we adults are. We have become afflicted with the jadedness of induction: the Earth hasn’t become uninhabitable yet and the rubber ball always bounces. And yet, paradoxically, the young child, in all her limited experience and gullibility, may be more right about the Fate of the Earth than we are  And yet she is far less powerful to do anything about it. 

Leave a Reply

Your email address will not be published. Required fields are marked *