25 February 2012

Why I'm an atheist, Part 3: Science & Certainty

In Part 2 I discussed the notion that the moral codes on which we actively collaborate are better suited to our way of life than those handed down from ancient times which are supposedly divinely inspired.

But why am I so certain that there is no deity giving us these moral mandates in the first place, you might ask. Well here's one more thing that I'm not saying when I say I'm an atheist: I'm not claiming to know with absolute certainty that there is no god or other supernatural entity in the universe. Maybe that sounds more like what you'd call agnosticism, but the fact of the matter is that the ideas of “atheism” and “agnosticism” are not mutually exclusive, and in fact most people who identify as atheists are also agnostics. The latter term is an acknowledgment that our knowledge of such matters will never be perfect. And at least in my case, it's an embracing of the logical methods of science as the best way to make statements about the nature of the universe. Science doesn't claim to know anything with absolute certainty, but its methods are the way to ensure that we're as close to the truth as is humanly possible. Science breaks a situation down to its constituent parts and makes sure we give each one due consideration before drawing any conclusions. 
While the popular image of “science” is of people mixing unpronounceable chemicals while wearing labcoats, it's actually a tool we all use. When you listen for a second or third sound, and in a specific pattern, before concluding that there's a burglar in your house while you're home alone in the middle of the night, you're using science. When you test brakes, acceleration, and turning in isolation and different combinations to narrow in on what the hell is wrong with your car this time, you're using science. And when you're holding your hand out a car window and try to remake a shape with your hand to see whether it was the shape or a random fluke of the wind that made your hand move a certain way, that's also using science. Now these examples aren't very rigorous science, so the certainty of your conclusions isn't going to be very high; if you really want to know if there's someone in the house you'll have to check more thoroughly, and you'd expect your mechanic to take a much more scientifically thorough approach by checking each possible cause in isolation so that they can be reasonably certain of their conclusion before telling you what you need to pay to replace. But even so these examples are taking advantage of aspects of the scientific method—accounting for and controlling variables; repetition—and even if your conclusions aren't airtight they're probably good enough for the immediate context.

We make use of repetition and controlled variables because while the world has certain predictable patterns it's also a random and chaotic place. If you're driving and hear a noise from under your car you know that it might have been a piece coming loose, though an object like a rock being thrown against the car could be (depending on the overall condition of your car) more likely. Even if it's not likely that a rock would bounce in that particular way or at that particular time, it's still plausible enough that it makes for a good first assumption; it's not efficient or effective or safe to pull over every time you hear a noise. Now, a change in the car's performance or gauges would be an obvious sign that something's amiss, but even if they're normal something could still be wrong. So you keep listening. You know that it'd be even less likely for another rock to hit in exactly the same way, so each additional time you hear the noise further rules out a rock as the cause. There are still plenty of other variables and plenty of other explanations than a broken component (again, it's not very rigorous science), but if you do keep hearing the noise it's probably time to pull over and check, regardless. (And of course even if there's no noise or change to gauges or performance, you should still check for problems when you come to your destination.)

As human beings we have a natural inclination to use the methods of science, even if we don't recognize them as such. We can see the logic in their application. We know that even though we can't be sure there's a piece hanging from the car until we get out and see it, that doesn't mean we can't reasonably conclude that there's the possibility for a dangerous situation if we don't pull over. Science isn't concerned with absolute statements of truth; it's concerned with what can most reasonably be concluded given the information at hand, our fallibility as human beings, and the chaotic nature of the universe.

An important feature of the above example is that once we do pull over and take a look, if a piece does happen to be hanging down and we see it we can be very, very certain that it's a problem and was the source of the noise. But let's go back to the earlier example of wondering whether there's a burglar in your home. Imagine you kept listening and weren't comfortably convinced that the sound you heard wasn't an intruder. There are plenty of other things that could make noises similar to a burglar in a home: wood creaking as it cools, the water or heat systems cycling, a breeze slamming a door or knocking something off a shelf, or maybe even another living thing in the form of a pet or pest. You could walk around the house and listen for the noise to repeat itself, and if it did you might be able to reasonably conclude it was just the wind, for example. But if you didn't hear the noise repeat itself, how could you be certain it wasn't an intruder? If you found him then you'd know for certain he was there, but how could you prove he wasn't? The fact is that it's near impossible to prove a negative. You could search your house top to bottom, every nook and cranny, multiple times and never see an intruder, but maybe he was constantly slinking about, staying just out of sight the entire time. It's incredibly unlikely, but depending on the size of your house, it could certainly be within the realm of human ability. And as the saying goes, absence of proof isn't the same as proof of absence. You could still prove he IS there, if he happened to slip up and you caught him, but if he isn't moving, taking, or leaving anything, then you'd have a very hard time proving he ISN'T there.

Now imagine this intruder had magic powers. Imagine he could make himself invisible, or could move through solid objects. And maybe if he does change things, he does it in a way that's indistinguishable from the actions of a natural force, like the wind. Now it would be totally impossible to prove he's not there. But consider this: if he's not interfering at all, does it really matter that he's there? For all practical purposes there would be no difference between him being there and him not. The absolute truth of his existence would be “out there” technically, but as a human being with limited sensory capacities, you wouldn't have access to it. (I'm ignoring things like thermal cameras or other sophisticated methods of detection for the sake of this example. You can imagine it all taking place in the Middle Ages or something if that makes it easier to swallow.) Given these exceptional circumstances, his existence and non-existence would be identical to human perception. And that may seem frustrating, that there's a truth out there that you can't know, but in the end, what difference does it make? You can go on living your life exactly as you would in a world without an invisible burglar in your house, and be no worse for it. So long as he doesn't interfere in any way, he's irrelevant to your life. 

And what if he did leave clues, but for one reason or another they were clues that only you could see? What if the only proof you had was that he sometimes talked to you at night? Well then you'd be out of luck, unfortunately. If there's nothing for the rest of us to work with, then we won't be able to bring ourselves to accept the existence of your invisible burglar. It's easy to forget where you left something, and voices are easily hallucinated. Subjective, anecdotal evidence isn't convincing; courts of law know that, and we in our guts know that. It wouldn't be what you'd want to hear, and it might not be the absolute truth of the situation, but it's the best we as your fellow human beings could do. Now if you were an outsider hearing a person talk about the invisible man in his house that no one else can see, you probably wouldn't be eager to create laws based on the supposed existence of this invisible man. As an outsider you'd probably assume this person claiming to have an invisible burglar in their home who didn't do anything substantial was suffering from some paranoia and/or mild hallucinations. You might not assume they were raving mad, but would probably think that they were letting their own imagination get away from them.

Most logical human beings would reject the idea of the invisible burglar. The facts of the situation don't coincide with what we know about how the world works. We have no evidence that the ability to become invisible exists, so we have no reason to believe that one person suddenly has it and is using it to harass some poor soul at night. It's an extraordinary claim. And as the saying goes, extraordinary claims require extraordinary evidence. Tell me you've got a pebble in your hand and I'll have little reason to disbelieve you, but tell me you've got a fairy in your hand and you better have some damn good evidence unless you want me to think you're just a little bit off (or just a bit of an ass, as the case may be).

The existence of a deity is an extraordinary claim. It also does not coincide with what we know of the natural world. The fact is that as time goes on, we are able to find more and more natural explanations for the phenomena we see around us. If you look back over history, there's a clear trend of religious explanations being supplanted by scientific ones. You just don't see the reverse. The more we learn, the more we see that the world could exist purely by the familiar laws of nature. Because of this, the universe is looking more and more like house in our little thought experiment: somebody's claiming that there's someone inside, but he can't be seen or detected and his actions are indistinguishable from the perfectly adequate natural explanations. 

Obviously we can be reasonably assured that there are no invisible burglars creeping about in our day-to-day lives, because such magic powers aren't within the realm of human abilities. But the definitions we have for gods are so grand that they escape this day-to-day level of certainty. Hell, we say most of them are omnipotent; an omnipotent being could certainly keep itself hidden from us if that was its desire, right? I admit that it's impossible to disprove the existence of an all-powerful being that either doesn't interfere or purposely masks its interferences. But just as a house that exists identically both with and without an invisible burglar gives us no reason to assume the burglar is there, so does a universe that exists identically both with and without a god give us no reason to assume a god is there. An undetectable god which leaves no tangible mark on the world may as well not exist. And if you ask me, isn't worth worrying about. Frankly, it would be about as deserving of the title "god" as our imaginary fellow who just sneaks around without stealing things would be of the term "burglar." So for us to concern ourselves with the existence of a god at all, there better be some evidence demonstrating that this universe doesn't operate exactly as it would without a god, and that's what we'll take a look at in the next post.

First, a brief aside. While a scheming invisible burglar is bit out-there, you don't have to be crazy to simply think of footsteps when you hear a creak at night. We all do it, and in fact it's a survival mechanism. The human brain naturally over-assumes “agency;” that is, it attributes a living and/or intelligent cause to more things than it should. And it makes sense to be wrong in that way, from a survival standpoint. It'd be better to assume that a rustling in the grass was a lion even if it was just the wind than to assume it was just the wind when it was really a lion. If you're going to err (and the ability to be absolutely correct every time isn't really within the precision available to evolution) then it's best to err on the side of caution. It's easy to see how this phenomenon could lead to the idea of tree spirits, fairies, and gods. The human brain is biased in a way to assume that wind doesn't just happenit must be sent by someone, or be a thinking entity itself. And before we had the capability to know about areas of high and low air pressure, those may have actually been the most reasonable assumptions. But careful logic and improved methods of detection can help us replace these instinctual mistakes with fact-based knowledge. At this point in human history we've accumulated the means to examine a huge number of the phenomena around us. And the picture that emerges is of a universe that operates without any intelligent input. Magnificent as the results may be, it's a world that chugs along autonomously purely on the laws of physics and chemistry. We have a logically-sound explanation for our universe wherein even awe-inspiring entities such as the huge, swirling galaxies and thinking creatures as we can be seen as the result of the properties of matter, energy, and their interactions. It can be tough to recognize and overcome our misleading instincts, but I think an honest person has to admit the undeniable logic behind our scientific explanations when presented with the evidence.

In Part 4 we'll discuss some of the supposed evidence for a god, and the evidence against it.

By the way, you may not have given a second thought to the idea of a person sneaking around your house, always just out of sight, but it's actually uncomfortably close to something that has indeed happened. Maybe it's best to keep an eye peeled. :P

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