Tuesday, 5 May 2009

What I Love About Einstein

I'm working my way through a copy of Robert W. Lawson's translation of Einstein's Relativity. This isn't a mathematical treatise, but a tiny paperback written by Einstein in 1916 to explain relativity to non-physicists.

It's a quaint little book, partly because of the language - but most strikingly by the way it stands in stark contrast to the modern era of predigested sound bites that deliberately pander to the gut instincts and short attention span of the intended audience.

As Einstein writes in the preface,
"Despite the shortness of the book, [it presumes] a fair amount of patience and force of will on the part of the reader."
I don't tote this around to look smart on the subway, that furrowed brow isn't deep thought so much as frustration at the fuzziness of my own mind. No, I picked this up after reading something about relativity and suddenly becoming desperately curious to learn just how Einstein was able to envision a description of the world so utterly different than the classical view that preceded it.

Not in the sense of, "My God, just how smart was he?" but literally: how do you make a discovery like this?

In case you're rusty, relativity is a refinement over the venerable Euclidean geometry, whose origins go back as far as 300 B. Euclidean geometry views of the world as composed of infinitely long straight lines, utterly flat planes, and perfect spheres. I first started learning it in primary school, and learned more about it for so many years afterwards that its abstracted, clinical view become second-nature to how I looked at every day things.

My kitchen table may not be a perfect plane, but that's table's problem, right?

As Einstein puts it,
"By reason of your past experience, you would certainly regard everyone with disdain who should pronounce even the most out-of-the-way proposition of this science to be untrue. But perhaps this feeling of proud certainty would leave you immediately if someone were to ask you: 'What, then, do you mean by the assertion that these propositions are true?'"
Geometry of any sort is just a mathematical contrivance, useful to the extent that it can be used to describe reality. If you get in a convertible driving 80 km/hr, and you throw a baseball ahead of you at 50 km/hr, classical mechanics would suggest that the baseball is would start off traveling at 130 km/hr, relative to the road. So far so good.

The key observation that spurred Einstein forward was the experimental discovery that the speed of light is not relative to the motion of the observer. Briefly, if you're zipping along at half the speed of light, and someone on the road shines a laser after you, classical mechanics would predict that the laser passes you at half the speed of light. What actually happens is that the laser light zips by you at full speed.

In fact, no matter how fast you're going, in whatever direction, light will still pass you at the same speed, regardless of the motion of the light source relative to you.

This is bizarrely counter-intuitive, to say the least - and if you think that's weird, the implications of Relativity are even more bizarre. The fact that Einstein came up with a rigorous geometry that made sense of this state of affairs was such a coup that his name became a household synonym for 'genius'.

The paradoxes of Relativity make for fascinating reading, but it's not my goal to rehash them here. What I want to do is highlight what Einstein had to do to get to a solution, and that was to question his own assumptions.

These weren't assumptions that had been given to him explicitly, like unjust laws he intuitively knew had to be overthrown and - dammit - he was the guy to do it! These were assumptions that nobody knew they held.

Imagine yourself doing a bit of math to try to figure out this speed of light business, and you find yourself muttering, "Hmm, divide this by the velocity.. carry the one.. and, oh yeah, I guess I'd assumed that distances were the same for everyone. Whoops." (erase erase erase) "And now multiply by the .. oh wait, I suppose I was assuming that time passes the same for all observers. How daft." (erase erase erase)

This doesn't happen every day. It requires a rare combination of precision of meaning, shaving each statement of belief into its component parts to be independently scrutinized, with the integrity to be willing to let go of any of them that don't pass muster, plus the courage and willpower to follow through with reconstituting the surviving pieces into a new worldview, however unfamiliar.

Whether or not your university calculus has rusted out of your head completely (as has mine), or if math has never been your friend, in an era where argument is increasingly reduced to punchy ad hominem attacks, this strikes me as an eminently worthy and useful mental posture to strive for.

That's what I love about Einstein.