Thursday, March 6, 2014

PZ Myers and the nature of evidence

PZ Myers
PZ Myers is, of course, the biology professor and atheist who writes at Pharyngula - a blog which probably gets more readers in an hour than I get in a year.

Er, I don't have to say that I don't agree with him about everything, right? I mean, I don't agree with anyone about everything, so why should I even have to mention that?

I do agree with him about most things, though, and I admire the way he writes (and thinks). As an example - and my whole point in writing this - I wanted to reblog a couple of excerpts I particularly liked from this post:
I see a pad of post-it notes next to my keyboard on my desk. This is clearly evidence that tiny invisible elves from 3M climbed up the wall outside my window, translocated extradimensionally through the glass into my office, and left me a present. Or is it evidence that I picked up a pad at the central office and put it in a convenient spot near my phone? You don’t get to say that the existence of this pad is equal evidence for both claims; you have to ignore the consilience of phenomena that provide better explanations. There is a cabinet of these things just down the hall from me; it’s a mundane object with obvious utility; there are torn-off post-it notes with scribbled comments attached to my phonebook. At the same time, 3M elves have no evidence for their existence, have posited powers with no known mechanism, and are arbitrary, ad hoc, bizarre explanations for a perfectly ordinary object. It is not demanding too much evidence to expect some independent corroboration of the mechanisms of the phenomenon that aren’t more simply explained by my ability to walk 50 feet to a collection of supplies.

In the same way, believers like to say they do have evidence for their supernatural phantasm…and then they point to their Bible. Sure, it’s evidence. Evidence backed up by documents and history that over the course of many centuries, human beings collected stories and legends and hectoring homilies and poetry, all written by people, and assembled them into a clumsy compilation, and stamped it all with the imprimatur of religious authority. Meanwhile, you’re trying to tell me this hunk of cellulose and ink was magically transported into the world of Catholicism by the equivalent of invisible elves.

Who actually has evidence for the origin of the object?

I like how he puts this. I hear from Christians all the time that they've got 'evidence' for their beliefs,... and then they point to the Bible without the slightest sense of irony. Or they say they've got "logical evidence," which apparently means an argument from incredulity.

Of course, I'm always pushing evidence-based thinking, so those are the kinds of responses I should expect to get, I guess. I mean, it seems simple to me, but apparently not to people who want to believe what they want to believe.

Here's another excerpt:
You know, this is the big difference. If you tell a scientist that their evidence doesn’t distinguish between two alternatives, it’s the scientist who thinks hard about the problem, comes up with what would be differing consequences of an experiment if his hypothesis was valid or invalid, and does the work. We actually love this part of theorizing, thinking through the implications of a hypothesis and then testing them. And that’s a process that involves getting specific about the details of our hypothesis.

Theologians, on the other hand, hate that part. We can ask them what the difference would be between a universe that had a god and one that didn’t, between a god that answers prayers and one that doesn’t, between a Christian god and a Muslim god, between a Catholic god and a Protestant god, and they love to tell us that the differences are profound, but not anything specific. And then they yell at us that we haven’t given them the criteria that we could use to discriminate between the alternatives. And then, most aggravatingly, if we go ahead and make some predictions ourselves about what the universe ought to be like if there is or isn’t a god, they yell even more that their god isn’t like that, we used the wrong premises, we didn’t address their idiosyncratic view of a god…which is always conveniently tailored to circumvent whatever test we propose.

Do you theological wankers even realize that as the proponents of hypothesis about the nature of the universe, it is your job to generate testable hypotheses about how it all works? And that we, as agents in opposition to your nonsense, would be overjoyed to have you say something explicit about an implication of your ideas that we could test? Actually, I think you do know, because you so invariably avoid presenting any useful descriptions of what your philosophy entails. We keep waiting. And right now, your silence and the vacuity of what few feeble replies you make are just added to our stockpile of evidence that you’re all farting theology out of your asses.

Yeah, he's not too popular with theists. It's always rather amazed me that theists demonize Richard Dawkins, who's normally so mild-mannered and understated, in that British way of his. PZ Myers, on the other hand, tends to breathe fire.

Of course, both are scientists. Both understand the nature of evidence. Both come from a community which values the truth, whether it's what they want to believe or not - a community which expects its members to do their very best to disprove their own hypotheses.

Science is evidence-based. That's why it progresses. That's why you can trust the scientific consensus, if there is one - not that it's guaranteed to be true, but that it's the very best answer we currently have. And if it isn't true, or not completely true (which is far more likely to be the case), you can trust scientists to be the first to discover that, and the consensus will change.

Most scientists, like most other people, were raised in a religious household. But they get this stuff, so they're far more likely than most to understand the problems with faith-based thinking.

Anyway, that's all. I just especially liked those two excerpts, so I thought I'd post them here, too.

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