Burden tennis is an intellectual parlor game, wherein the players “hit” the “burden of proof” across the net from one side to the other.  We see this expressed as “the burden is in your court” or “the burden of proof is yours”, with often both sides making similar statements.

Burden tennis can be a fun game to watch, but it is sometimes wiser to avoid being a participant.

Note:  I did not invent the term “burden tennis”.  I saw that being used on the net somewhere many years ago.  But it seems like a good term.

This post is really a reply to Patrick’s post in the moderation thread.  I’ve started a new thread, because the discussion really doesn’t belong there.

As far as I know, the expression “burden of proof” comes from law.  With the assumption that the defendent is innocent until the charges are proved, the burden of proof is initially with the prosecution.

Even in courts, the standard of evidence is “proof beyond a reasonable doubt” for criminal trials, and “the preponderance of evidence” for civil trials.  Both of those standards fall short of “demonstrated fact”.  And both are ambiguous in meaning and ultimately up to the subjective judgment of the jurors.

I largely agree with hotshoe_ about this.  The frequent demand for facts sometimes gets out of hand.

If I had required factual evidence for everything that my school teachers said, I would never have graduated out of kindergarten.  The demand for evidence seems to come from the idea that “knowledge is justified true belief.”  I see that as an absurd definition of knowledge.  Children do learn from stories such as “Little Red Riding Hood” even though they know it is fiction.  They aren’t learning facts.  They are learning ways of interacting with other people and with the external world.

If I open a newspaper (either print or online), I may come across a sudoku puzzle and a crossword puzzle.  Solving the sudoku puzzle is completely a matter of facts and logical reasoning.  But solving a crossword puzzle has very little to do with facts.  The clues are often ambiguous, and deliberately so.  We never know if we have the correct answer to a specific clue, where “correct” means “intended by the puzzle author.”  But, when we are done, we see that all of the answers fit together in such a way that it is highly likely that we have the correct solution.

In what follows, I’ll use the terms “sudoku evidence” and “crossword evidence”.

Sudoku evidence: demonstrated facts that lead to a logical conclusion.

Crossword evidence: things all fit together in such a way that the conclusion seems highly likely (or “consilience”).

When I deny that “knowledge = justified true belief”, I’m really suggesting that the bulk of our knowledge is in the form of a wealth of causal connections into the world such as would allow us to make good decisions based on crossword evidence.

Most of what we do and learn in life depends on crossword evidence, rather than sudoku evidence.  At this forum, we sometimes see Frankie/JoeG asserting that there is no evidence for evolution.  Presumably he is talking about sudoku evidence, and he might be right about that.  But there’s a wealth of crossword evidence.

So, back to the burden of proof.

My own view is that the burden of proof lies with the one who wants to persuade others.  When hotshoe_ says “Now I accept that as a consequence you may choose not to believe that I have stated a fact” she is saying that she is not particularly concerned whether others are persuaded.  So, on my view, there is no burden of proof.  And if others do not accept what she said, there is no burden of proof on them either.  There can be a lot of useful and informative discussion without playing burden tennis.  And most of our decision making in ordinary life is based on crossword evidence.  Likewise, science is very much dependent on crossword evidence.  Mathematics mostly depends on sudoku evidence.  However, setting up a new and useful axiom system can depend on crossword evidence.

Open for discussion.