Saturday, May 8, 2010

Action at a Distance

My imagination has recently been piqued by an explanation of Newton's law of gravity. For all that he contributed to physics, he famously did not bother to explain why gravity works. It's academically referred to as a black box theory, perhaps the most famous one. And today, why gravity works remains a mystery. Similar black box theories - those which forego describing any mechanism - are occasionally studied and occasionally derided depending on their context.

The Universe — Beyond The Big Bang — History.com Videos

That a theory - or more like a law, or set of laws - needs no explanation is counterintuitive but also strangely liberating.

When I learn something, my instinct is to wrap my head around it - to get a feel for it from all angles, to compare and contrast it to other bits of knowledge, and to try to grasp the underlying principles that make it fit together. Perhaps that's just the normal response: we seek to understand things.

Newton's curious depiction of gravity, on the other hand, separates learning from understanding.

And beyond separating the two, it suggests that understanding might actually set you back. His theory was largely resisted for some time because it lacked an underlying explanation. Its utility and predictive power overcame this hurdle.

Following Einstein, the current consensus is that some laws of the universe are so distant from our scale of experience that we can't be expected to understand their mechanism, much less intuitively grasp them. There's an intuitive appeal in this explanation about how difficult it is to grasp very large and very small things. But that doesn't make it true.

Returning to Newton, one question I've been asking myself is whether similar black box explanations may apply to things of an everyday scale. It goes against every fiber of scientific thought: Theories with meager explanations seem less plausible and poorly thought out. And yet it seems strangely plausible - that principles may be unfolding on a human-scale which we couldn't fathom - if only as a possibility.

At the least, this line of thought emphasizes the role of observation and empiricism. As 'theoretical' as the notion of gravity is, its proposal still required real-world observation - without that, it would have made absolutely no sense.

The scientific method suggests that we have our presuppositions and hypotheses about how the world works, and then data is used to either back them up or to falsify them. But perhaps the take-home message is that the reverse is at least possible, namely that we start with data and then learn how it fits together. And where a set of awkward principles - such as action at a distance, which, let's face it, sounds more like magic than physics - so perfectly consolidates the data, understanding might be ignored, be it temporarily or deliberately.
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