Observing the Past to Refute Cranks in the Present

No one seems to care about the difference between observations (or 'facts') and inferences like creationist-types do. That's not to say that the distinction is unimportant or that scientists don't pay any attention to it, but creationists really care about it. That's because in order to make the world fit within their scriptural boundaries they have to discount large amounts of science from a variety of fields. However, they can't just dismiss science without looking like medieval relics, so they take upon themselves the task of separating 'true science' from 'false science' so that they can appear to be sophisticated lovers of science. One of the simplest ways to make that separation is to insist that the unacceptable parts of science are actually stacks of unreliable and/or un-provable inferences. Thus any statement about the ancient past or processes that occur over long periods of time can be met with the simple question: Were you there?

Before getting to my main point, I can't help but comment on how radically skeptical such people would be in general if they were more consistent in their pedantry, because inference is everywhere. Nor, I think, do they realize how many unobjectionable 'facts' are actually built on inference. Pick up any molecular biology journal, for example, and you will find lots of measurements. But those measurements are often done using indirect methods (because nobody can directly observe a molecule) [1], and the phenomena they measure are often correlates or indicators of broader phenomena. However, today's inferences become tomorrow's facts as they are demonstrated to be reliable and useful in advancing knowledge. As Stephen J. Gould put it, "In science, 'fact' can only mean 'confirmed to such a degree that it would be perverse to withhold provisional assent.'" Occasionally accepted facts are revised as their underpinnings are probed in more detail--often because of advancements in technology. It's just the nature of the beast. Or life in general, really.

That brings me to my main point. The National Center for Science Education (NCSE) advocates and provides support for teaching evolution and, more recently, climate science in schools. Their most recent Reports periodical has a fun article, Yes, We Were There, by a physicist (and Christian) named Antoine Bret. After setting up the 'Were you there?' issue, Bret describes several interlocking observations that show that the laws of physics have been constant for over 30,000 years--less than a drop in the bucket of the accepted age of the universe, but more than the Biblical age of the Earth.

The progression of his argument is as follows:

1. Stars have been measured to be 30,000 light years from Earth by the parallax method, which is based on trigonometry. Approximately 30,000 light years away is the limit of detection for this method, but he chose it because it is the most direct method in terms of observation.

2. We can measure the spectra emitted by the elements in those stars, which match those of the elements on Earth. The signature spectra are explained by quantum mechanics, in which the speed of light is a key component. This shows that the speed of light has not changed in the last 30,000 years. So unless you want to say that God created the universe with light already in transit (something hardcore creationists believe), these observations show that the universe is at least (!) 30,000 years old.

3. Various types of supernova beyond 30,000 light years away have been observed, and the nuclear decay of their elements tracked. The rates of radioactive decay match those on Earth.

Bret concludes:

Physicists do not hold that the laws of physics haven’t changed over the last 30000+ years because of a uniformitarian prejudice. They hold it because this is what they observe....for all practical purposes, “we were there” to see it.

I suspect that it might be more accurate to say that physicists had no reason to think that the law of physics had changed, but that these observations simply add direct support to their confidence.

So does this argument prove that the laws of physics haven't changed? I'm sure there are counter-arguments to be made. For example, I guess you could argue that the Earth was in a special bubble where the laws of physics were different from those of the stars. But where are the observations that would substantiate that?

Notes:

1. I'm thinking of things like western blots, ELISA, or especially flow cytometry. We run various controls to be confident in the results, but the end result is technically an inference. Similarly, blood cholesterol is measured via a series of chemical reactions that result in a color change, which is measured by light absorbance. Is your LDL number really a fact? You can see how this game can be played to the nth degree.

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