Watcha Gott?

I was thinking about the Copernican Principle recently, and recalled an article sent to me by good friend RD. I went to look up the article he had sent, which was probably a summary of the Gott article cited below, but instead found the response I sent to him. Below is a brief overview of the principle and Gott's article, and I'm sure an online search would yield more detail if you're interested.

Copernican principle (from Wikipedia)

In cosmology, the Copernican principle, named after Nicolaus Copernicus, states the Earth is not in a central, specially favoured position. More recently, the principle is generalised to the relativistic concept that humans are not privileged observers of the universe. In this sense, it is equivalent to the mediocrity principle, with significant implications in the philosophy of science.

Since the 1990s, the term has been used (interchangeably with "the Copernicus method") for J. Richard Gott's Bayesian inference-based prediction of duration of ongoing events, a generalized version of the Doomsday argument.

Hypothesis

Nature 363, 315 - 319 (27 May 1993); doi:10.1038/363315a0

Implications of the Copernican principle for our future prospects

J. Richard Gott III

Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA

Making only the assumption that you are a random intelligent observer, limits for the total longevity of our species of 0.2 million to 8 million years can be derived at the 95% confidence level. Further consideration indicates that we are unlikely to colonize the Galaxy, and that we are likely to have a higher population than the median for intelligent species.

Hi [RD]:

Sorry for the delay in responding, but I’ve actually been thinking about this article on and off for a while. As best as I can determine it’s bad news for God, but really doesn’t affect the rest of us too much. The reason is it is really hard (for me) to think of many instances where Gott’s assertions would apply, since a key premise is that no other information, particularly in a temporal sense, is available and applicable beyond the current observation. But how many things are there for which we have absolutely no experience or, and here’s the important part, perceived analogous experience or relevant information? (which is probably why so many things taste like chicken)

The second key premise (the Copernican principle), the concept that there is probably nothing terribly special about the current observation, situation, object, etc., is a profound one and points to elements of human nature (values, desire for control, importance, etc.). More specifically, the principle encourages us to view information objectively rather than subjectively. Good point, but easier said than done, and some would say impossible.

Thirdly, Gott uses probability as the basis for his calculations, relying on the old academic standard of two standard deviations, or 95% about the mean. For a two-tailed test, that’s 2.5% on each end, and voila, the observation is somewhere between 1/40th remaining and 1/40th completed. It could just as easily have been assume you’re equally likely to have the remaining time more or less than the observed/confirmed time (now at the midpoint), or use one standard deviation (somewhere between 1/6th remaining and 1/6th completed), etc.

And now the fun begins. As you might expect, I see this as marketing. Instead of saying, “If you have no pertinent information about the observation, assume that the observation is random,” say that “If you have no pertinent information about the observation, apply the reasoning of Copernicus.” That is clever in the way it allows us common folk to have easy access to and application of the thoughts of a genius. People love deep, complex truths that may be expressed and understood in shallow and simple ways. (Whatever happened to EST, transcendental meditation, and a thousand similar revealed truths?) And I like the way it subtly critiques “The world revolves around me” mentality. This is not to demean the value of such a “Copernican concept,” as divorcing biases, preconceptions, etc., is important. Just give Gott credit for thinking of a catchy name for it. Also, probability plays a central role in my life and thinking, and I think it’s good that people learn to apply it more. The fact that the statistical standard chosen is arbitrary but consistent with orthodox notions of confidence levels- fine, why not. So it’s good that Gott gets us away from subjective thinking and encourages the use of statistics in addressing an “unknown.” However, how much is really completely “unknown?”

Now we are at the nub of it. I think that you have to apply the Copernican principle in order to apply the Copernican principle. That is, in order to conclude that the observation is random and that no other pertinent information is available and applicable, you have to assume that which you conclude. Maybe it is safer to argue that whatever information we have is likely of little value, and maybe even harmful (in which case we be out of a job). But maybe it is more useful to try to figure out how to better use what is available. Gott gives us some tools, and that’s good. But how about analyzing, deducing, inferring, discovering, and whatever else we can do to find patterns , relationships, explanations, etc., that will allow us to make more than a Gott prediction? I’m not saying that the Red Sox win when I wear my red shirt, the slot machine is ready to hit, or she is my one and only soulmate… it’s just that the availability and applicability of information may be more than we know.

Gee, I just wanted to say thanks for the article, and here I am an hour later having taken up too much of your time. According to Gott, I’ve somewhere between two minutes and 40 hours left to go.

-Dave