5.6.1: Not Accepting the Burden of Proof

If a neighbor says, "Jeff slit the tires on my son Jeremy's bike," he is expressing his opinion. An opinion is a belief. But is his opinion also a fact? Maybe. He can show it is a fact if he can prove it to be true. If he expects to convince other people of his opinion, it is his duty to prove it. A proof of a statement is an argument for that statement that ought to be convincing; it doesn't need to be the sort of thing you would find in a math book. You prove a statement to other persons if you give them reasons that ought to convince them, even if those reasons don't actually convince them. The important point is that people don’t know something if they are not justified in believing it.

Sometimes, it isn't obvious who has the burden of proof. If two people each make a statement disagreeing with the other, who has the heavier burden of proof? You can't tell by asking, "Who spoke first?" Usually the burden is on the shoulders of the person who makes the strangest statement. A statement is considered strange if it would be likely not to be accepted by the majority of experts in the area under discussion. People who make controversial statements have the greater burden of proving their statements.

The claim that an alleged mass murderer is innocent may be unacceptable to people in a community because the community members have been convinced of his guilt by media coverage. Nevertheless, the burden of proof does not rest with those who make the controversial claim of his innocence; it still rests with those who assert his guilt. The legal experts would say that the controversial claim is the claim that he is guilty before the trial has concluded.

There are other problems in determining where the burden lies. In the late twentieth century, an English researcher discovered a poem inserted between two pages of an obscure book in the Bodleian Library of Oxford University in England.¹ The poem was handwritten by a seventeenth-century scribe who attributed it to William Shakespeare. Surprisingly, however, this poem was not part of the currently known works of Shakespeare. Was it really by Shakespeare? That's the question. Examination of the paper and ink verified that the poem was indeed copied in the seventeenth century. Shakespeare himself died in the early seventeenth century. The poem is clearly written in the style of a Shakespearean poem, although it is not an especially good poem. The researcher is convinced the poem is Shakespeare's. At this point, does the researcher have the burden of providing more proof, or does the skeptic have the burden of proving the poem is not Shakespeare's?

The burden of proof has now shifted to the skeptic, not on the person who said it was written by Shakespeare. Unfortunately, it takes expertise to know this. Because of how the poem was discovered, when it was copied, and the style it is written in, experts on English poetry generally concede that the case has been made in favor of Shakespeare, as author, and the burden is on somebody to show he was not the author. Many skeptical researchers have analyzed the poem, looking at such things as the number of words that aren't in any of Shakespeare's other works, but they have failed to prove their case.

Exercise \(\PageIndex{1}\)

Jeremy says, "My goldfish are dumb, dumb, dumb. They don't know one-tenth as much about the world as I do." David responds, "You can't say that. Maybe we just can't communicate with your fish." Who has the greater burden of proof in this dispute?

Answer

Jeremy doesn't. He is simply making a claim that agrees with common sense. Since David is challenging common sense, he has the greater burden of proving his claim.

---

¹ Adapted from remarks made in program 20 of the syndicated TV series “Against All Odds: Inside Statistics,” copyright by The Consortium of Mathematics and its Applications, Inc., 1988.