I've been meaning to write about epistemology and science for quite a while....
The problem is that there really isn't a single simple place to dig in and get started. Why not? Because all of what we'd call "human knowledge" is connected; if you intend to explain one piece completely you'd eventually wind up trying to explain it all. That's why the 6-year-old child's tactic of asking "why?" is so successful and annoying.
kid: "why is the sky blue?"
mjr: "because of diffraction in the atmosphere."
mjr: "well it's got to do with how light's frequency changes when you bend its path."
mjr option 1: "don't ask me, go dig up Richard Feynman."
mjr option 2: "it's time for you to go to bed."
But there's a really wonderful thing about scientific knowledge and its connectedness: it doesn't contradict itself. Not anywhere. Or, rather, not for very long; contradictions mean something is wrong with the theories that allow us to understand whatever it is that we're talking about. Scientists get really really excited when there's a potential contradiction in an important theory, since it represents a fascinating new problem to figure out.
You may recall the recent news about neutrinos appearing to have moved faster than the speed of light. Idiots in the media got excited and published articles entitled "Einstein's Relativity: Overthrown?" etc. There was some excitement in the scientific community but most of the more reasoned responses were very cautious: relativity has been exhaustively measured and the speed of light does, indeed, appear to be the hard limit. My favorite observation on the topic was from Ethan Siegel on his wonderful "starts with a bang" blog. He pointed out that measurements of the arriving neutrinos emitted by a supernovas and the light of the supernova's explosion are accurate to parts per billion (the gravitation of other stuff between the supernova and us is going to affect light differently from neutrinos, but not much) so the measurements that were 60 nanoseconds from what was expected - was probably wrong. And, immediately, the physics community was buzzing with possible things that the OPERA team might have gotten wrong, and experiments that don't show the effect, etc. This is how science is done: claims that are radically inconsistent with theory get scrutinized very closely indeed. Not because scientists are a bunch of dweeby pissants, but because the high-tech world in which we live depends to a certain degree on the consistency of scientific claims. There are things that, if they were shown to be wrong, would be very, very interesting, indeed.
There are other things that are shown to be right, for all intents and purposes. For example, if someone came along and claimed that the speed of light was something else, scientists would laugh at them. And, rightly so. Because every single GPS is - in a sense - one great big experiment that proves that the speed of light is correct. A ground-based transmitter sends a signal to satellites in geosynchronous orbit, which is then reflected back down to earth where it's read by your handheld receiver. The difference in the receipt-time of the signal is calculated based on the known position of the satellites and, because of how long it takes the signal to travel at the speed of light, the unit is able to tell where it is relative to the satellites. Pretty cool. We can be said to "know" that the speed of light is what we think it is because it allows us to predict outcomes and, when they're tested against the theory, sure enough things come out right. Another example of a predictable outcome measuring the speed of light is the computer you're using to read this: if scientists' idea of the speed of light were very wrong, your computer would not work correctly. Modern processors are so fine and complex that knowing the amount of distance an electron will move at the speed of light, during a memory fetch/clock cycle is crucial to designing the chip.
Epistemology is the study of systems of knowledge. Put another way, "how do you know that?" is really the ultimate question that we're concerned with. One good answer to "how do you know that?" is "because I have a theory that predicts certain things with great accuracy and, when I measure in accordance with the theory, then that's how it comes out every single time." When you're dealing with a body of knowledge as complex and interdependent as our current scientific understanding of the universe, you're left with the choice of either accepting it or rejecting all of it, because it's becoming increasingly difficult to attack one piece of the body of scientific knowledge without attacking, basically, all of it. One of the best ways you can tell that you're arguing with someone poorly educated is if they claim "science doesn't know everything!" in defense of some (whatever) weird belief or other. Why? Because virtually any claim that you can make, at some point, is going to touch upon something objectively measurable or observable, which - in turn - is going to have to fit with the rest of scientific knowledge. A shorter response to the "science doesn't know everything!" claim is, "yes, but you know even less." What a lot of people don't realize is how amazingly far we humans have come since the 18th century. While physicists today are searching for grand unified "theory of everything" the working theories that they have about reality are, simply, ridiculously good. For example, Isaac Newton's physics is good enough for most of what we'd want to do, until you get to very fast, precise, small things or big things like computers, space travel, GPS, differential wireless broadband, lasers, etc. When people say "Newton was wrong" what they really should be saying was "Newton was right, for all intents and purposes, within the limits of the technology of his time." One of the reasons that it took until Einstein to expand and refine Newton was because Newton was so damn right. If you look at the rate at which there are massive scientific overthrows of theory, it has pretty much dropped to zero since Einstein. We are not going to see another Copernican revolution, in which suddenly "OMG! Teh erfs iz not center of universe? LOL!" everything changes.
Scientists seem to me to be fairly dismissive of philosophy, because all too frequently, philosophy makes claims that have something to do with objective reality, but which do not follow from any kind of theory with predictive power. The scientist interprets that as "bullshit" while the philosopher interprets it as "profound argument." Nowhere is this conflict more apparent than in discussions of claims of the supernatural. Of course, the ultimate claim of the supernatural is made by religion - but let's steer away from that, for now. Let's think, instead, in terms of ways of making claims of knowledge. I.e.: epistemology.
The most important dichotomy when talking about "the supernatural" (whatever that is) is embodied in the very word "supernatural." It's "super" (in the sense of the old Latin word implying 'over' or 'superior') to the "natural" or nature. Something that is "supernatural" is, "outside of nature" "unnatural" or "other than nature" - we don't need to parse the words particularly finely at this point. Claiming that something is "supernatural" is a fairly common tactic of argument when a rationalist is debating a, uh, well, other-than-naturalist because the other-than-naturalist (can I call them "supernaturalist"?) wants to deflect scientific enquiry about their pet topic.
Let me illustrate:
Supernaturalist: "I believe in ghosts."
Scientist: "Cool! Do you have any evidence for the ghosts?"
Supernaturalist: "No; they are outside of what science understands!"
So far, so good. What we've seen is a claim, a response asking for evidence, and then a counter-claim that attempts to place the initial claim off-limits.
David Hume and Skepticism
David Hume (1711-1776) [I originally wrote: "pronounced "Home"" but it turns out I had that completely backwards. Hume's name was originally "Home" pronounced 'Hyoom" and he changed his name to match its pronounciation. What an embarrassing mistake, and a top 'o the hat to the deviant who corrected me!] is one of the most famous philosophers of the enlightenment and was largely responsible for re-introducing and reformulating ancient Greek skeptical thinking into the corpus of western philosophy.
(David Hume, could out-consume....)
I labored long and hard to craft that previous sentence, because I didn't want to seem like I was giving Hume too little credit; he was incredibly brilliant and his contributions to thinking were profound. Much of his thinking regarding skepticism appears to be heavily influenced by some of the writings of the ancient Greek skeptics, in particular Sextus Empiricus (160-210ad). The ancient Greek skeptics were, by all measures, incredibly annoying men, who appear to have been the first to formulate the philosophical equivalent of nuclear weapons: "I don't believe you even exist, nyaa nyaa nyaa!" Sextus Empiricus' "outlines of pyrronism" is one of the classics of philosopy, and it outlines a series of rational arguments that demolish epistemology. Unless you're a philosopher, it's hard to imagine how utterly annoying pyrronian skepticism can be - the skeptic adopts a position of making no claims of knowledge whatsoever, and forces his opponent to flail around helplessly trying to say anything at all. I suspect that arguing with Sextus Empiricus would have been quite fun, but the end-game would sound like the dialog with a 5-year-old:
Skeptic: "How do you claim to know about 'gravity'?"
mjr: "Because, physics predicts how gravity behaves, and it always behaves according to physical law"
Skeptic: "How do you know that?"
mjr: "Because so far no contradictory experiment has been observed."
Skeptic: "How do you know that?"
The philosophical works of ancient Greece were suppressed in Europe during the dark ages and the rise of the church because, as you can imagine, having a skeptic raise his hand and interrupt the pope with infinitely regressive questions is extremely annoying if you're the pope. What Hume did was present readable, upgraded, and more circuitous versions of some of Sextus' arguments at a time when enlightenment philosophers like Descartes and Leibniz were beginning to wrestle with the relationship of science to the supernatural. Hume's reframing of the old skeptical arguments was intellectual nuclear weapons. Crucially, he observed that:
- Our senses are subject to falsehood or misinterpretation
- Everything we think or do or learn must come to us through our senses
- Therefore everything we think or do or learn is suspect and any argument based on it is unfounded
Following Sextus Empiricus, he doesn't simply attack a given epistemology or system of knowledge - he attacks our ability to have a system of knowledge.
A Supernatural Dialectic
Now, we're ready to resume the little dialog with the supernaturalist that I started above. If you'll recall, it went something like this:
Supernaturalist: "I believe in ghosts."
Scientist: "Cool! Do you have any evidence for the ghosts?"
Supernaturalist: "No; they are outside of what science understands!"
Now, our scientist whips out a brain-demolishing dose of 2nd century skepticism and asks
Scientist: "If they are outside of what science understands, how can you possibly know they are there? Because any possible way you'd have of knowing about them is subject to scientific enquiry."
At this point, the supernaturalist usually plays the "science doesn't know everything!" dodge, which is the rhetorical equivalent of tipping over your king and walking away from the chess-board in a huff.
But, the conundrum remains inescapable: how can you make claims to knowledge about something that you also claim is outside of your own ability to know?
If you wish to be a brain-busting skeptic who destroys supernaturalists, all you have to do is try to get them to identify the point at which their belief systems move outside of observable reality. Once you can localize your opponent's claim to knowledge, then you crush it with skeptical enquiry. The simple head-on skeptical attack is going to give your victim enough of a chance to stomp away from the table before taking full damage. If you want to really rattle them, use gentle loops of epistemological enquiry, combined with fact-checking. Here's an example:
Acupuncturist: "Acupuncture works by manipulating the body's energy field."
Skeptic: "Interesting! 'Energy' is cool stuff. Did you know that scientists have organized all the forms of energy into a frequency chart called 'The Electromagnetic Spectrum' that goes, basically, from zero to cosmic rays. It's just a way of organizing all the different forms of light, radio waves, etc. So, do you know where on the spectrum acupuncture operates?"*
At this point, the acupuncturist's best strategy is to run like hell. But there are a couple of different end-games:
Acupuncturist: "Science doesn't know everything!"
Skeptic:" Actually, when it comes to the electromagnetic spectrum, we do! Isn't that cool!? We used to not be sure where cosmic rays came from but in 1999 scientists conclusively measured cosmic ray-bursts from a supernova and now we're 100% sure that they're 'just' subatomic particles that got whacked to light-speed by the explosion of a supernova. So our understanding of the whole electromagnetic spectrum is now complete. And, of course some parts of the spectrum are too high-energy, because we'd measure all kinds of interactions if the acupuncture was at the higher end of the spectrum. I mean, we're talking stuff that makes X-rays look like a pat on the back. So, uh, where did you say acupuncture works again?"
Acupuncturist: "It's not part of the electromagnetic spectrum!"
Skeptic: "Then what is it?"
Back to Ghosts
The "alternative thinker" loses control of their ability to claim knowlege when they protect it by trying to take it off the game-board. To stick with the chess metaphor, it's like protecting your queen from being captured by hiding her in your pocket: she can't be taken but she can't exert any influence in the game, either. In a nutshell, this is why religion has been being edged into irrelevance by modern knowledge and technology: religion can't make a GPS work, or, actually, make any useful claims of knowledge whatsoever.
What's odd to me is that skeptical thinking usually stops at the first claims that attempt to place a topic outside of the scope of scientific enquiry. But, if you think about it, just like the rest of science, claims that in any way lead to knowledge have to survive all possible scientific enquiries. Which brings me to ghosts.
Let's suppose there's a thing called a "ghost" that is 'supernatural' - which, for the sake of argument, means that it's some kind of super-special thing that "science doesn't understand." And it's in the room with us. Eek! But wait, here's the first problem:
- How do we know it's in the room with us?
Perhaps, we see it? Well, if we see it that means that, somehow, for it to register in our eyes it's interacting with (technically: absorbing and emitting photons) light. If it's not interacting with light, we can't see it; that's how our eyes work. Light interacts with our atmosphere and scatters (which is why the sky looks like the part of the electromagnetic spectrum we call "blue", or 450-500 nanometers) for a ghost to be visible, it's got to - well - exist as we define "existence" i.e.: be made of stuff. There's no such thing as something "immaterial" that interacts with light.
But wait, you say, the ghost appears and disappears? That would mean that it's doing some pretty cool tricks - material appearing and disappearing could be a violation of some of the conservation laws. You don't just have matter (which is made of atoms) suddenly vanish. Not without a change in energy that we certainly wouldn't miss. (A-bomb explosions are an example of what happens when matter is converted into energy; we'd certainly all believe in ghosts if they did that on a regular basis)
Here's my favorite idea about ghosts: if the ghost is "in the room" with us that means that it's somehow interacting with gravity. Only things that have mass do that, so for a ghost to be "in the room" with us it'd have to have mass. Because otherwise it would have no inertia (right?) and Earth would go whipping along at its normal speed of 67,000 miles/hour and the ghost would be left behind. It wouldn't even be "in the room" with us long enough to start to go "boo!" (our solar system is also moving at a godawful speed in another direction, and our galaxy in yet another, and space-time is also expanding, so our poor massless ghost, even if it could move, would have a hell of a time figuring out where to be) And, let's not get started on the problem of "how do you move when you're massless?" Newton was right about the action/reaction thing, so what would our poor ghost push against? And, of course, you have to be able to push against something in order to make sound, so a massless ghost couldn't even go "boo!"
The point of all of this is that anyone with a moderate science education not only knows that ghosts are bunk, they ought to be able to see not just one problem with the idea; there are lots. Yet we sit there and nod complacently while idiots talk about them as if they're real. It's not that there's no evidence for ghosts - it's that there's active evidence against "ghosts" as they are conceived or described. The only description of a "ghost" that fits physical law is "nonexistent" which means that there's no way you can claim to know it exists, because it doesn't exist. I don't mean "doesn't exist as we know it" I mean, "doesn't exist as we define 'existence'"
There are many things in popular culture that fail the epistemology challenge. Yet, because we're generally imaginative and hopeful creatures, we still treat them as though they might exist. In spite of not merely lack of evidence that they do exist, but overwhelming evidence that they do not. Here I am referring specifically to things like life after death, "souls" and gods. Consider life after death: you have a physical being, which consists of a bunch of matter containing some electrical signals and a bunch of other interesting states of purely "real" stuff that comprise what we call "life." When we stop living (by the way, that's not a clear-cut event except for in the brain of the person experiencing it) some of those states start to change, especially the electrical signals in our brains. There's no way those signals could somehow go somplace else without it being quite obvious and measurable. Even if you wanted to posit a spare dimension above and beyond our 3+time that we're used to, the transition from real stuff to stuff in another dimension would be very noticeable (and extremely exciting!) to scientists. No, what happens is that the chemical pumps that charge the neurons in your brain run out of the stuff they need to drive the Krebs cycle and other metabolites - and stop. Then the electrochemical firings stop and the emergent property known as "consciousness" comes apart and disappears the same way that a "bottle" loses its "bottle-ness" when you hit it with a sledgehammer. Any more complex transition happening at death would very obviously give itself away by producing unexpected heat (or radiation!) or something, in accordance with physical law. In fact the only transition that can happen upon death that's in accordance with physical law is the one I described; stuff just stops and the very temporary self-organization we call "life" disintegrates. Not "goes away" - disintegrates.
Are there ghosts? Life after death? Last summer, two very good friends of mine passed away, and I mourn them still. I remember their lives and the time we spent together and if I close my eyes I can remember what it felt like to hold them, the smell of their hair, the sound of their breathing, the times we played and danced together - I'll remember them as long as I live. They had other friends than me, too, who also remember them (different memories, to be sure, but with some commonalities) When I eventually die and disintegrate, those ghosts in my brain those memories will be gone with me. And, eventually, as the rest of the people who knew them forget them, or die in turn, their "ghosts" will finally fall away. To me, that seems soothing and natural.
* a brief side-note on acupuncture: If the theory of acupuncture is that it's a medical intervention, i.e.: that it causes some kind of positive health benefit or cure, we'd expect to be able to measure long-term side-effects. This is an obvious fact which is used in clinical trials of drugs, etc.: you give a group of patients your new cancer drug and, over time, you measure for a shift in the morbidity rate (doctor-ese for: "who dies and when") over time. If your new cancer drug works, you'll eventually observe that patients treated with it tend to live longer than those who aren't. So, we can disprove that acupuncture confers any benefit in two ways: one, we can compare it to a placebo and we observe that generally people report positive benefits of acupuncture at the same rate and to the same degree as patients treated with a placebo. That leads us to the inescapable conclusion that "acupuncture is a placebo." But the deadlier argument is simply this: if acupuncture was used for hundreds or thousands of years by Chinese doctors, we'd expect to see that life-spans in China were, for a long time, superior to the rest of the world's. Of course we see no such thing - human life-spans were around 35 years more or less until Henri Pasteur figured out the bacterial model of infection, ushering in the age of modern medicine, and life-spans have nearly doubled world-wide since then. We do notice correlations between life-span and the wealth of a society, still, but acupuncture doesn't even show up as a blip on any experiment except for the ones comparing it to a placebo. Case closed.