Q&A: Observing Jewish Law Under Uncertainty
Observing Jewish Law Under Uncertainty
Question
Hello Rabbi Michi,
I wanted to ask: if a person believes with 99% certainty that the Torah is true, why is it proper for him to observe commandments 100% of the time? Doesn’t the Rabbi think it would make sense that 1% of the time (about 14 minutes a day) he could do whatever he wants? I mean, the common understanding is that once a person has decided the “doubt” in the religious direction, his attitude toward reality is as though it were “certain.” But why?
It’s more comfortable for me to ask this question by email; it feels to me like a forbidden act of incitement and leading astray for the evil inclination to post it on your wonderful site. 🙂
Answer
First, I don’t accept the consideration about incitement and leading astray. On the contrary, this is a question that may trouble others too, and it is important to discuss it. Therefore I’m moving it to the site.
As for the question itself, I do not understand how you infer from the probability that a theory is correct to the percentage of time we should act according to it. For example, suppose the probability that aerodynamics is correct is 97%. Does that mean that in your opinion, 3% of the time we should refrain from using airplanes? It seems to me that if there is a high probability that X is the truth, then one should act according to X all the time. The calculation is that at every moment when you are deliberating whether to do X or not, the decision is made again and again in favor of X.
Discussion on Answer
It seems to me that in practice what happens in such a situation is 100% of the time observing commandments with 99% intensity.
“Intensity”?
This reminds me of Professor Aumann’s remarks, a quote from Wikipedia:
“Aumann disagrees with prospect theory, developed by Amos Tversky and Daniel Kahneman (the latter received the Nobel Prize for it), according to which human behavior in probabilistic situations is not rational. He explains the researchers’ mistake by saying that there is a difference between a person’s behavior in a familiar situation and in a situation that is not part of his ordinary experience. Even if in unfamiliar situations a person acts irrationally, in familiar situations he will behave differently. Thus, for example, subjects who were asked to guess the color of a light that would turn on in front of them, when the probability of a green light was 75% and of a red light 25%, guessed green three times and red once (the rational decision, assuming these are independent events, is always to guess green). However, if those same subjects are faced with the everyday question of which route to take home, they will always travel by the route that is fastest most of the time.”