2 ms·

Why would anyone ever put 0% then? I would just redefine "impossible" to be an arbitrary percentage that guarantees I don't nuke the question. Quick question:

by Cyph0n 10y ago

Why would anyone ever put 0% then? I would just redefine "impossible" to be an arbitrary percentage that guarantees I don't nuke the question. Quick question: is confidence taken in percent form (ln(90)) or decimal form (ln(0.9))? Edit: I am aware of the implication of having percent values, guys/gals. But if it's in decimal form, a 5% confidence level will end up losing you the current question AND three others.

hexane360 10y ago
If it was in percent form, a correct answer with 100% confidence would be 1 + ln(100) = 5.605 pts. Only ln(1) = 0.
derefr 10y ago
I assume that was part of the lesson: in Bayesian decision theory, an agent that assigns 0.0 or 1.0 confidence to something can no longer update on new evidence about that thing. Saying something is 0% likely means being so sure about that thing, that nothing—no matter how amazing—could or would ever change your mind. Basically, no human is actually ever 0.0 or 1.0 sure of anything. Assign five or ten nines of confidence, but not 0.0 or 1.0. (It's a lot clearer when you remove the log scale and notice that a 1.0 confidence-value translates to you saying you're "infinitely confident", which seems ridiculous.)
- jumpCastle 10y ago
  But then what is my confidence that God exists? I would say zero because of the spaghetti monster argument
  - Cyph0n 10y ago
    He's right though, you can never be truly certain that some kind of God doesn't exist. But if you're referring to a specific God, then maybe.
- hyperpape 10y ago
  I suppose this is a bad place to ask this, but given that you need to do math to update your credences and also that you can derive any proposition from Pr('2 + 2 = 4) != 1, how does this work?
  - derefr 10y ago
    Basically: probabilities and credences aren't the same thing. They're measured on the same scale, but probabilities can be used to reason about either facts or evidence, while credences are only "about" evidence (though potentially evidence about facts.) To put that another way: it is "100% true" that 2 + 2 = 4 (in ZF set theory); just like it is "100% true" that the sun will rise today, because it already did (and otherwise the Monty Hall problem would have a different answer.) But the credence in an agent's mind can and should only be informed by observations of these facts; and the "observing hardware" cannot be 1.0 trustworthy. (Your senses can be imprecise; the brain can be buggy or biased; the environment being observed can be the construction of a Cartesian "evil demon"; etc.) Given an artificial agent with perfect knowledge (e.g. one who is able to directly entangle itself with the environment it is trying to predict, rather than just one able to entangle itself with evidence about the state of an environment), some things can theoretically be held to have 0.0 or 1.0 probabilities (e.g. events that already happened)—but given an embodied agent, the "maybe my processing is flawed" argument should still make these into non-infinite credences.
    - hyperpape 10y ago
      Thanks. I should've remembered that the connection to an agent's credences and their judgments of probabilities is complicated.
    - platz 10y ago
      If the Higgs field quantum tunnels to a lower energy level today in our vincinity, the sun will not rise tomorrow. Never put 100%
      - derefr 10y ago
        I didn't say "the sun will rise tomorrow"; I said "the sun will rise today"—as in, the (trivial) probability that the sunrise that already happened, will happen, looking forward from the more distant past to the more recent past. Given that we are talking about the probability of that event occurring from a reality where it occurred, the updated probability of it occurring is 100%. (But we cannot have 100% credence, simply because we can't actually be 100% sure we're in said reality.)
cornstalks 10y ago
I'm not whack, but it must be in decimal form, or else putting 100% on a correct answer would yield ~5.6 instead of 1 (which whack says would be the score).

by Cyph0n 10y ago

hexane360 10y ago

If it was in percent form, a correct answer with 100% confidence would be 1 + ln(100) = 5.605 pts. Only ln(1) = 0.

derefr 10y ago

I assume that was part of the lesson: in Bayesian decision theory, an agent that assigns 0.0 or 1.0 confidence to something can no longer update on new evidence about that thing. Saying something is 0% likely means being so sure about that thing, that nothing—no matter how amazing—could or would ever change your mind. Basically, no human is actually ever 0.0 or 1.0 sure of anything. Assign five or ten nines of confidence, but not 0.0 or 1.0. (It's a lot clearer when you remove the log scale and notice that a 1.0 confidence-value translates to you saying you're "infinitely confident", which seems ridiculous.)

jumpCastle 10y ago
But then what is my confidence that God exists? I would say zero because of the spaghetti monster argument
- Cyph0n 10y ago
  He's right though, you can never be truly certain that some kind of God doesn't exist. But if you're referring to a specific God, then maybe.
hyperpape 10y ago
I suppose this is a bad place to ask this, but given that you need to do math to update your credences and also that you can derive any proposition from Pr('2 + 2 = 4) != 1, how does this work?
- derefr 10y ago
  Basically: probabilities and credences aren't the same thing. They're measured on the same scale, but probabilities can be used to reason about either facts or evidence, while credences are only "about" evidence (though potentially evidence about facts.) To put that another way: it is "100% true" that 2 + 2 = 4 (in ZF set theory); just like it is "100% true" that the sun will rise today, because it already did (and otherwise the Monty Hall problem would have a different answer.) But the credence in an agent's mind can and should only be informed by observations of these facts; and the "observing hardware" cannot be 1.0 trustworthy. (Your senses can be imprecise; the brain can be buggy or biased; the environment being observed can be the construction of a Cartesian "evil demon"; etc.) Given an artificial agent with perfect knowledge (e.g. one who is able to directly entangle itself with the environment it is trying to predict, rather than just one able to entangle itself with evidence about the state of an environment), some things can theoretically be held to have 0.0 or 1.0 probabilities (e.g. events that already happened)—but given an embodied agent, the "maybe my processing is flawed" argument should still make these into non-infinite credences.
  - hyperpape 10y ago
    Thanks. I should've remembered that the connection to an agent's credences and their judgments of probabilities is complicated.
  - platz 10y ago
    If the Higgs field quantum tunnels to a lower energy level today in our vincinity, the sun will not rise tomorrow. Never put 100%
    - derefr 10y ago
      I didn't say "the sun will rise tomorrow"; I said "the sun will rise today"—as in, the (trivial) probability that the sunrise that already happened, will happen, looking forward from the more distant past to the more recent past. Given that we are talking about the probability of that event occurring from a reality where it occurred, the updated probability of it occurring is 100%. (But we cannot have 100% credence, simply because we can't actually be 100% sure we're in said reality.)

cornstalks 10y ago

I'm not whack, but it must be in decimal form, or else putting 100% on a correct answer would yield ~5.6 instead of 1 (which whack says would be the score).