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Bob has a very simple algorithm to output probabilities. He just answers 50/50 for any yes or no question. This is reproducible. Is this objective?

by ikeboy 6y ago

baobabKoodaa 6y ago
This doesn't strike me as a good example of reproducibility in this context. Let me offer another one. Let's go back to your example of the 66% weighted coin. Given the physical properties of the coin, different people could independently come to the same conclusion that the probability of heads is 66%. I would describe this as an "objective" probability, as it's a nice representation of the available information, independently reproducible by different people, given the same information. It's different than "Bob arbitrarily decides that any yes/no question has 50/50 probability", which is inherently subjective.
- ikeboy 6y ago
  No two people ever have the same set of information. And very few cases are even as clean as the coin case. A more typical example is using polls to predict elections. 538's model ended with Biden around 90% to win. Andrew Gelman's model at the Economist ended with Biden around 95%. Do either of those represent objective probabilities? Or take weather predictions. Per https://www.metaculus.com/questions/4617/will-2020-be-the-warmest-year-on-record/#comment-46010 https://www.metaculus.com/questions/4617/will-2020-be-the-wa..., Berkeley Earth gives a 16% chance to something that NOAA gives 29.2% to. Is either of those an objective probability? I would say no, and I think that just because two people happen to agree on a number in a particular case doesn't make it objective. If you want to use the word objective, I don't have any particular objection. I'm not here to fight over words, and none of these words are really well defined enough to be worth fighting over. I don't think it's useful to think of probabilities as "real" in any sense.
xvedejas 6y ago
Yeah, that's objective. It's just not a great model.

Bob has a very simple algorithm to output probabilities. He just answers 50/50 for any yes or no question. This is reproducible. Is this objective?

by ikeboy 6y ago

Bob has a very simple algorithm to output probabilities. He just answers 50/50 for any yes or no question. This is reproducible. Is this objective?

baobabKoodaa 6y ago

This doesn't strike me as a good example of reproducibility in this context. Let me offer another one. Let's go back to your example of the 66% weighted coin. Given the physical properties of the coin, different people could independently come to the same conclusion that the probability of heads is 66%. I would describe this as an "objective" probability, as it's a nice representation of the available information, independently reproducible by different people, given the same information. It's different than "Bob arbitrarily decides that any yes/no question has 50/50 probability", which is inherently subjective.

ikeboy 6y ago
No two people ever have the same set of information. And very few cases are even as clean as the coin case. A more typical example is using polls to predict elections. 538's model ended with Biden around 90% to win. Andrew Gelman's model at the Economist ended with Biden around 95%. Do either of those represent objective probabilities? Or take weather predictions. Per https://www.metaculus.com/questions/4617/will-2020-be-the-warmest-year-on-record/#comment-46010 https://www.metaculus.com/questions/4617/will-2020-be-the-wa..., Berkeley Earth gives a 16% chance to something that NOAA gives 29.2% to. Is either of those an objective probability? I would say no, and I think that just because two people happen to agree on a number in a particular case doesn't make it objective. If you want to use the word objective, I don't have any particular objection. I'm not here to fight over words, and none of these words are really well defined enough to be worth fighting over. I don't think it's useful to think of probabilities as "real" in any sense.

xvedejas 6y ago

Yeah, that's objective. It's just not a great model.