Observational Selection

Transcript: The weak form of the anthropic principle in essence states that we can only live in a universe that has the properties such that we can exist. In other words, we can only exist in the universe and should not be surprised that the universe has the properties to allow long-lived stars to exist and carbon to have been created. This sounds like a truism or a tautology, but the anthropic principle elevates it to a level of a scientific theory with hopefully predictive powers. It may not have predictive powers due to the prospect of observational selection. Consider an example of a fish story. You catch a fish that is 23.2576 inches long, exactly that long, in a lake. Then, afterwards, you test your apparatus and discover that it could only have caught a fish this length to within one part in a million. This is the analog of the fine tuning that the universe exhibits in its fundamental properties. From this information do you conclude a) that the lake has many fish of different lengths and you eventually found the one that you could catch, or b) that there is only one fish created by a deity who wanted you to catch it? These are the two possible ways you can look at the anthropic principle.