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The goal is to explain "why is the number this value and not some other value". Unless the number actually takes on multiple values, the anthropic principle has
by tbabb 11y ago
The goal is to explain "why is the number this value and not some other value". Unless the number actually takes on multiple values, the anthropic principle has no explanatory power.
If there is only one value, the universe can't "plan" or "choose" a value that is conducive to life, and so pointing to its suitability for life is a teleological argument-- it explains a cause (the value of the constant) in terms of its effect (the eventual existence of life). That's backwards and circular-- causes come before effects.
- Houshalter 11y agoThink of it in terms of Bayes theorem. The probability of observing a constant that doesn't support life is 0, since we wouldn't exist. So the probability of observing constants that just happen to support life is 1, and so it shouldn't be surprising at all. If it wasn't that way, we just wouldn't exist to ask the question.
- tbabb 11y agoWhat on Earth has that got to do with Bayes' theorem? What's your prior? All you did was re-state the anthropic principle.
- fenomas 11y agoI think the point is that there's no question of causality between values of constants and the existence of life, just conditionality, which is what Bayes knows how to talk about. That is, the anthropic principle doesn't try to "explain" why a constant takes a value. It just notes that the conditional property of us observing that value (given that we exist) is 1, regardless of what the unconditional property might be (or even whether it's variable to begin with).
- tbabb 11y agoIf this is Bayes, then what is the prior probability distribution over the values the fine structure constant could take?