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There's plenty of empirical evidence for 2 + 2 = 4, it's just so pervasive that we fail to recognize it as such. Take two apples, place them on a table. Now tak

by jey 19y ago

There's plenty of empirical evidence for 2 + 2 = 4, it's just so pervasive that we fail to recognize it as such. Take two apples, place them on a table. Now take two more apples, and place them on the table. How many apples are on the table? 3? 4? 5? I have an astronomically high probability assigned to "2+2=4", but if I kept doing this experiment and suddenly ended up with 3 apples every time, I'd have to decrease the probability I assign to 2+2=4, and increase the probability assigned to 2+2=3. The apples example is from "How to Convince me that 2 + 2 = 3": http://www.overcomingbias.com/2007/09/how-to-convince.html http://www.overcomingbias.com/2007/09/how-to-convince.html Interesting essay on Bayesian reasoning: http://yudkowsky.net/bayes/technical.html http://yudkowsky.net/bayes/technical.html

aston 19y ago
I don't disagree, but my hypothetical assumes that no one has done the experiment before making their belief known.
- jey 19y ago
  Sounds like an unreasonable assumption. Either way, it's not about "wrong" or "right", it's only about what can be derived from evidence. Without evidence you have no justification to assign a higher probability to "2 + 2 = 4" than "2 + 2 = 3". Caveat: It's true that some knowledge does have to be put into the prior distribution. Apparently you can't just bootstrap from a zero-information ("maximum entropy") prior. So it's possible that 2 + 2 = 4 is burned into our brains at birth.
  - whacked_new 19y ago
    > So it's possible that 2 + 2 = 4 is burned into our brains at birth. Yup, there is plentiful evidence... not specifically the addition, but 2 and 4 are innately perceptible quantities.
Tichy 19y ago
From the article: "But from a Bayesian perspective, you need an amount of evidence roughly equivalent to the complexity of the hypothesis" But what is the "complexity of the hypothesis"? Without a proper definition, there is not much left to the article, or is there?
- Eliezer 19y ago
  Fixed with linky.
cellis 19y ago
By my contribution, I am guilty by association. But do you realize how pointless this discussion is getting? Ha. Only on hacker news. 2+2 = 4. Thus it is written.
- jey 19y ago
  IMHO, I think Bayesianism is more interesting than a lot of the stuff discussed here. The idea that all reasoning can be done as Bayesian inference is pretty damn cool. If someone looks at the above and thinks "Whoa, Bayesianism is neat! I should go read more about it!" then I'm happy, but if everyone is just thinking "Duh, of course 2 + 2 = 4"... well, shit.

by jey 19y ago

aston 19y ago

I don't disagree, but my hypothetical assumes that no one has done the experiment before making their belief known.

jey 19y ago
Sounds like an unreasonable assumption. Either way, it's not about "wrong" or "right", it's only about what can be derived from evidence. Without evidence you have no justification to assign a higher probability to "2 + 2 = 4" than "2 + 2 = 3". Caveat: It's true that some knowledge does have to be put into the prior distribution. Apparently you can't just bootstrap from a zero-information ("maximum entropy") prior. So it's possible that 2 + 2 = 4 is burned into our brains at birth.
- whacked_new 19y ago
  > So it's possible that 2 + 2 = 4 is burned into our brains at birth. Yup, there is plentiful evidence... not specifically the addition, but 2 and 4 are innately perceptible quantities.

Tichy 19y ago

From the article: "But from a Bayesian perspective, you need an amount of evidence roughly equivalent to the complexity of the hypothesis" But what is the "complexity of the hypothesis"? Without a proper definition, there is not much left to the article, or is there?

Eliezer 19y ago
Fixed with linky.

cellis 19y ago

By my contribution, I am guilty by association. But do you realize how pointless this discussion is getting? Ha. Only on hacker news. 2+2 = 4. Thus it is written.

jey 19y ago
IMHO, I think Bayesianism is more interesting than a lot of the stuff discussed here. The idea that all reasoning can be done as Bayesian inference is pretty damn cool. If someone looks at the above and thinks "Whoa, Bayesianism is neat! I should go read more about it!" then I'm happy, but if everyone is just thinking "Duh, of course 2 + 2 = 4"... well, shit.