Sunday, April 10, 2005

Richards Revisits Relativity

In this post from last Tuesday, I took pro-ID blogger Jay Richrds to task for suggesting that he had discovered a flaw in Einstein's reasoning about relativity.

Well, Mr. Richards has now updated the post in which he made that suggestion. The update, in its entirety, runs as follows:

Update: In this post, I erred in not clearly distinguishing Jim Holt's summary of Einstein's argument, from Einstein's argument itself. (Incidentally, I am not a skeptic of special or general relativity. Nor am I an expert on either.)

Holt claimed (as have other science writers) that Einstein showed that time is a fiction. That's not correct, either in fact or as an interpretation of Einstein. What Einstein argued is that time is relative. What does that mean? Physicist David Mobley offers this helpful critique of my post and explanation of special relativity.

Allow me to refresh your memory as to what Richards said in his original post:

Similarities aside, Holt summarizes Einstein's argument on special relativity nicely, so nicely, in fact, that it reveals what I have long suspected is a mistake in Einstein's argument.

So the idea that Richards simply erred in not carefully distinguishing Einstein's argument from Holt's summary of that argument does not really hold water. The phrase “...what I have long suspected is a mistake in Einstein's argument” makes it clear that Holt's article was merely the excuse to bring up the subject. The error, says Richards clearly, lies with Einstein.

But no matter. Let us move on to the other problem with this update. Contrary to Richards' assertion, Holt does not claim that Einstein showed that time was a fiction. (David Mobley makes the same error in the link above, but his post is worth reading anyway for its interesting description of relativity).

Here is what Holt actually said:

A century ago, in 1905, Einstein proved that time, as it had been understood by scientist and layman alike, was a fiction. (Emphasis added).

Holt clarifies this point later on:

Suppose—to make things vivid—that the speed of light is a hundred miles an hour. Now suppose I am standing by the side of the road and I see a light beam pass by at this speed. Then I see you chasing after it in a car at sixty miles an hour. To me, it appears that the light beam is outpacing you by forty miles an hour. But you, from inside your car, must see the beam escaping you at a hundred miles an hour, just as you would if you were standing still: that is what the light principle demands. What if you gun your engine and speed up to ninety-nine miles an hour? Now I see the beam of light outpacing you by just one mile an hour. Yet to you, inside the car, the beam is still racing ahead at a hundred miles an hour, despite your increased speed. How can this be? Speed, of course, equals distance divided by time. Evidently, the faster you go in your car, the shorter your ruler must become and the slower your clock must tick relative to mine; that is the only way we can continue to agree on the speed of light. (If I were to pull out a pair of binoculars and look at your speeding car, I would actually see its length contracted and you moving in slow motion inside.) So Einstein set about recasting the laws of physics accordingly. To make these laws absolute, he made distance and time relative.

It was the sacrifice of absolute time that was most stunning. Isaac Newton believed that time was regulated by a sort of cosmic grandfather clock. “Absolute, true, mathematical time, of itself, and from its own nature, flows equably without relation to anything external,” he declared at the beginning of his “Principia.” Einstein, however, realized that our idea of time is something we abstract from our experience with rhythmic phenomena: heartbeats, planetary rotations and revolutions, the ticking of clocks.

Nowhere does Holt say Einstein showed that time is a fiction. In fact, his article does an excellent job of describing the basic elements of Einstein's reasoning.

There's a lesson in this. When an ID proponent describes someone else's work, always go back and check the original source. And if the original source is not available, assume that the ID proponent is misrepresenting it.


At 8:08 AM, Blogger Bill Ware said...

The Sunday NY Times crossword puzzle is a tribute to Einstein. It includes his observation: "The only reason for time is so that everything doesn't happen at once."

At 1:52 PM, Anonymous Anonymous said...

Funny thing that Holt's description reminds me so much of George Gamow's in (I believe) Mr. Thompkins in Wonderland.

--Dave Lewin


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