“I don’t think there’s anything he could say that would convince me – I need hard evidence,” said an atheist friend when I invited him to come with me to  a presentation on the reliability of the Bible. That got me thinking about evidence and our desire for more of it. After all, “seeing is believing,” right?

This November marks the 100th anniversary of Albert Einstein publishing his theory of general relativity. Only 10 years earlier, in 1905, Einstein had published not one, but four, paradigm-shifting papers, including his special theory of relativity and his proposal of mass-energy equivalence, from which we get the famous equation E=mc². Since then, his theories have been repeatedly confirmed. Special and general relativity did not simply provide a competing theory compared to classical Newtonian physics; they encompassed Newtonian physics. In relatively weak gravitational fields, special relativity reduced to Newtonian formulas at speeds much slower than the speed of light (our typical earthbound experience). General relativity expanded on that to provide an explanatory framework that could account for objects travelling at all speeds and through any gravitational field. It explained what Newtonian physics could and couldn’t explain. That’s powerful.

How did Einstein develop this powerful theory? Can you tour the lab where he huddled over a workbench full of special scientific equipment, or see the telescope he tirelessly spent long nights peering through, looking for evidence of gravitational lensing, or examine his lab journals of dutifully recorded experimental results? Not really. Einstein worked as a simple patent clerk in his “miracle year” of 1905, and was still doing “thought experiments” when he developed general relativity. He was short on evidence, but long on problems to think through. He proposed 3 scenarios unexplained by Newtonian physics that relativity would need to correctly explain for it to be true: 1) the slight changes in Mercury’s orbit around the sun already observed by others, 2) the deflection of light by the sun that Newtonian physics predicted, but not accurately, and 3) the color change (redshift) of light passing through a gravitational field that was completely unverifiable at that time.[1] While he could compare his theory’s predictions to  Mercury’s orbital changes measured by others, he had no way to confirm the other 2 tests. In fact, the evidence to support his theory only trickled in over many years, the most conclusive confirmations  of it after his death in 1955. Sir Arthur Eddington confirmed the deflection of light by the sun’s gravity in 1919 when he measured the slight curvature of starlight bending in the gravitational field of the sun during a solar eclipse. But it was decades before sufficiently precise measurements could confirm gravity’s miniscule color-shifting effect on light here on earth. In the years since, though, several other effects have verified Einstein’s unproven theory.

In fact, Einstein’s general theory of relativity touches most of our everyday lives  in one very real, but surprising way. Our cars, planes, cellphones, and even wristwatches now have the ability to tell us where we are because a of wonderful cold-war invention called GPS. But engineers designing the GPS satellites originally didn’t think they would need to account for gravitational redshift in the signal timing. This change in color of visible light is actually an effect of time dilation; time actually runs faster in a weaker gravitational field. And so the clock on a GPS satellite will run 38 microseconds faster, per day, than the same clock on earth, which is enough to produce invalid location results. This would also handicap our cell phones that use this precise timing to handle transferring calls to new cell towers seamlessly.

So did the lack of hard evidence in any way detract from the truthfulness of his theory? No, that’s because we don’t create truth, we only discover it. If something is true, it’s true whether we know it or not, and whether we understand it yet or not. The GPS clocks ran faster whether the original engineers admitted it or not, and whether you and I fully understand it or not. Can Christianity be true without measurable, scientific evidence? Absolutely.[2] But there’s a deeper question here. Is experimental observation the only way we come to know truth? No. In fact, the “thought experiments” Einstein relied on were simply exercises in sound reasoning that scientists, mathematicians, and philosophers have used for millennia. As Einstein understood, there are many times where it is impossible to obtain “hard evidence” for something. It may be a unique, non-repeatable event, or it may be something infeasible to test at the present time, but that doesn’t have to stop us from investigating. Albert Einstein didn’t limit himself to experimental evidence, but rather used his mind to go where science couldn’t yet, and he changed the world. Don’t let your desire for a certain type of evidence keep you from investigating the truth of Christianity and changing your world.

[1] Albert Einstein, Relativity: The Special and the General Theory (New York: Barnes & Noble, 2004), p. 87-88.
[2] Not that there isn’t a wealth of evidence for the truth of the Bible, but that’s a subject for another day.