Thursday, December 22, 2011

Epistemology a la Franklin

"in this world nothing can be said to be certain, except death and taxes"
Benjamin Franklin

Philosophers use words such as "truth", "belief" and "knowledge" in a restricted sense and formal way. Most of us use these words much less formally. We can say "I believe you will like this" or "I think you will like this" or even "I know you will like this" interchangeably when we might more accurately state "I hope that you may like this". On the other hand, we sometimes restrict these words to specific domains, so that we talk about "religious beliefs" and "technological knowledge". I fear that people are misled about the accuracy and precision of their ideas by the way they use these words.

I tend to assume that. in formal terms, all knowledge claims have implicit aspects of the credence with which they are held or the credibility with which they are transmitted. One might say "I am 90 percent sure" or "I am pretty sure". I suspect that few of those claims are to be accepted as quantitative. (An exception might be a statement such as "in a survey, 90 percent of respondents reported that they knew that the earth revolved around the sun?.)

Maybe because I am old and forgetful, I realize that some of the things that I think to be true are not true. Ask my wife if she can depend on my actually having done things around the house that I think I have done. And of course when you are depending on reports from others, they not only may have misremembered but may be communicating poorly or falsely,

A scientific study might report that a value is between a and b, with 95 percent confidence. What that really means is that "on the basis of our experiment we would only expect a value outside of the range from a to b once in 20 times, but of course there may be an unrecognized error in our experimental apparatus or procedure."
"The art of concluding from experience and observation consists in evaluating probabilities, in estimating if they are high or numerous enough to constitute proof. This type of calculation is more complicated and more difficult than one might think. It demands a great sagacity generally above the power of common people. The success of charlatans, sorcerors, and alchemists — and all those who abuse public credulity — is founded on errors in this type of calculation."
Benjamin Franklin and Antoine Lavoisier
It seems that betting might give us hints as to how to quantify confidence in our beliefs or knowledge. For example, one might ask what odds one would have to have to bet on being right. That is a model which has only limited areas of applicability.
  • For example, I think that there is probably other life in the universe. However, any bet on that postulate would be completely theoretical since there would be no way in my lifetime to demonstrate it to be false.
  • There is pretty good evidence from the way punters bet on horse racing that people make systematic errors in betting, too often overestimating the probability of longshots winning and underestimating the probability of favorites winning. On the other hand, people are pretty good at ranking alternatives on the probability that they will turn out to be right. Incidentally, the willingness to bet on being right is not only a matter of the odds one gets, but also the amount one stands to lose. I might bet two dollars on a horse at a given set of odds, but not 1000 dollars.
I wonder why it seems that people are much more ready to use violence in defense of beliefs which are based on faith and not evidence than they are in defense of hypotheses based on both theories that have met the test of many tests and professional review as well as a controlled observations.

I love the comment made by Benjamin Franklin on the last day of the constitutional convention:
I confess that there are several parts of this constitution which I do not at present approve, but I am not sure I shall never approve them: For having lived long, I have experienced many instances of being obliged by better information, or fuller consideration, to change opinions even on important subjects, which I once thought right, but found to be otherwise. It is therefore that the older I grow, the more apt I am to doubt my own judgment, and to pay more respect to the judgment of others. Most men indeed as well as most sects in Religion, think themselves in possession of all truth, and that wherever others differ from them it is so far error. Steele a Protestant in a Dedication tells the Pope, that the only difference between our Churches in their opinions of the certainty of their doctrines is, the Church of Rome is infallible and the Church of England is never in the wrong. But though many private persons think almost as highly of their own infallibility as of that of their sect, few express it so naturally as a certain french lady, who in a dispute with her sister, said "I don't know how it happens, Sister but I meet with no body but myself, that's always in the right — Il n'y a que moi qui a toujours raison."

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