Archive for January 10th, 2013

January 10, 2013

HSW – Against induction

by Neil Rickert

In this post, I shall argue against induction.  Specifically, I shall argue against what I referred to as “philosophic induction” in a recent post.  My earlier post — “All emeralds are green” — was intended to illustrate the view that I shall be presenting here.  I suggest you read that now, if you have not already done so.  Throughout this post, I shall assume familiarity with that story.

That emeralds are green has sometimes been used to illustrate the idea of induction.  Presumably, the argument would be:

  • All the many emeralds that I have seen were green;
  • Therefore all emeralds are green.

Interestingly, emeralds were also used by Nelson Goodman in his skeptical “grue” argument.

read more »

January 10, 2013

All emeralds are green

by Neil Rickert

This is a completely made up story, that I intend to reference in a future post about induction.

Long, long ago in the small village of D’La Mere, the residents lived a relatively simple life.  They were employed in a number of different kinds of work.  Some of them would go daily to the village quarry, and collect pebbles that they could spread on their walking paths to inhibit the growth of weeds and to keep the paths from becoming muddy when it rained.

While Peter, one of the residents, was at the quarry loading gravel into his wheelbarrow, he noticed a green glint in one of those pebbles.  Looking more closely, he could see something green and perhaps crystalline behind a rocky outer crust.  He pocketed that pebble, and later took it to his friend David, a craftsman.  David was able to chip away the outer rocky crust to reveal the gleaming green part that remained.  He made it into an ornament that Peter could give to his girlfriend.

On receiving the ornament, Peter’s girlfriend Angela said “That’s very nice of you, Peter.  So what shall I call this?”  After thinking for a moment, Peter replied, “If we spell the name of our town backwards, we can use that and call it an emerald.”  “I love that name,” said Angela, giving Peter a kiss.

Word soon spread through the small village, and before long several of the residents had found emeralds.  Making emerald rings and bracelets was becoming a cottage industry.  The village mayor was very pleased at this.  So he asked Peter, “What can you tell me about emeralds?”  And Peter replied, “Since we find them by looking for the glint of green light reflecting from them, we can say that all emeralds are green.”