My housemates and I got into an argument about global warming friday night. This is not an infreqeunt occurence at 3739 Regent Avenue; we are an interesting mix.
I forget how the subject was brought up, but the argument started when Tim said “I know the earth is getting warmer, but I don’t know whether humans are to blame.” I asked him how he knew it was getting warmer, and he said that a majority of climate scientists would say it was getting warmer.
My argument was that Tim had never talked to a climate scientist or read one of their papers; he had only (to the best of my knowledge, anyhow) heard summaries of papers, as reported by members of the press. I contended the only way you could really know that the earth was getting warmer would be to conduct the experiments yourself, or read a paper written by someone who had conducted the experiments, verifying that their methodology was correct.
Kevin told me he found this line of thinking arrogant; he said that he recognized expertise and that if a majority of climate scientists felt the earth was getting warmer and that humans were to blame, most likely they were correct. I responded that majority has no place in true science, that scientists are frequently wrong, and there have been many times in the history of scientific development when the ‘community consensus’ was used to stifle ideas originally considered far-fetched that turned out to be correct.
I wrote about this almost example a year ago, in the case of Marconi. At that time, I took kevin’s viewpoint – Marconi ignored conventional scientific wisdom and, as I saw it, got lucky when that wisdom turned out to be incorrect. I defended the scientists who told Marconi he was a fool for trying to send radio signals across the atlantic.
I think very differently now. My reasoning is this: Marconi’s detractors told him he couldn’t send signals across the atlantic because the curvature of the earth would prevent the signals from crossing the atlantic. They made a prediction – It is not possible to send radio waves distances that are on the order of the radius of the earth – based upon a mathematical model of the universe.
Where’d this model come from? Mathematical characterizations of past observations. A bunch of people saw a bunch of different stuff, and over the course of human history, the more mathematically inclined observers devised a framework that categorized past observations.
We use that framework to make predictions about our future, but in doing so we make an assumption: things will happen in the future in the same way that they’ve happened in the past. If we say it is impossible for event X to occur, what we are saying, ultimately, is ‘X has never happened in the past, and things that did not happen in the past will not happen in the future, therefore, X will not happen in the future.’
Is that line of thinking logical? It’s consistent with a set of axioms, so yes. Does the set of axioms make sense? Yes, but only if you’re careful about generalizing your framework. That’s been the goal of science – to build a framework as general as possible. A good example of this is the struggle to develop a unified theory of physics that fixes the discrepancies between quantum mechanics and general relativity. We’d rather not have two sets of rules describing how things work, one for small scales and one for large scales.
If your framework is too specific, however, you can look really foolish. For example: I have never been to France. Things that did not happen in the past will not happen in the future. Therefore, I will never go to France. You’d be laughed at if you tried to make this argument seriously. Yet it’s really the same argument scientists make when they say you can’t build a perpetual motion machine: Nobody’s ever been able to produce energy for free before. Things that did not happen in the past will not happen in the future. Therefore, nobody will ever be able to produce energy for free.
As I see it, physics is really a mathematical study of our history, coupled with the assumption that there is a simple framework that can describe everythng we will experience in the universe, and that by mathmatically characterizing past events, we can accurately predict future events. For this reason, i’m more interested in math and (especially) computer science. I think the best way to understand our universe is to study those generalizations we’re creating, so we can understand their limitations.
When you get right down to it, i feel like there’s no reasonable way you can argue that something isn’t possible. All you can do is say “We’ve never encountered that before.”
As to our discussion on global warming, the Marconi example is particularly suitable for my argument. Marconi was able to send his radio waves becuase of the ionosphere, a layer of the atmosphere that refelects radio waves. The scientists of his day didn’t understand the atmosphere like they thought they did, and were therefore incorrect to tell him he couldn’t send radio signals across the atlantic. My argument to my housemates was twofold, which is probably why I didn’t make much sense to them. The first, less interesting argument, was that you shouldn’t talk about scientific subjects unless you’ve read the literature and understand it and can make the arguments yourself. I’m not sure how common this viewpoint is, and I’m not really even sure if it’s mine, because I trust ‘experts’ all the time.
The second, more interesting argument was “Knowing scientists have been wrong in the past, particularly on the issue of the environment, what makes you so sure they’re not wrong now?”
When I realized where our argument was going I decided to just give up and go to bed. I recognize I can be a crank when it comes to my scientific ideas, and there were people over who had no interest in the discussion.
What do you think?