Friday, November 09, 2007


A visiting scientist, on science

One great thing about working in the research arm of a major corporation is that we occasionally bring in leading scientists for visits and talks. The other day, I was pleased to host Dr Jill Tarter, Director of the Center for SETI Research. We gave Dr Tarter a full schedule: a formal presentation in the afternoon, a round-table lunch for informal conversation, and meetings the rest of the day with various research groups.

I hope that the day was half as interesting to Dr Tarter as it was to us — I’ve received several good comments from folks who met with her, and the presentation drew about 120 people, between the auditorium and the remote video link. And it was a privilege for me to have the chance to join the group for lunch, and just bat things around.

I’d like to highlight a thing or two here that Dr Tarter said in her presentation. SETI, the Search for Extra-Terrestrial Intelligence, is actually, she says, a search for extra-terrestrial technology. The technology — in this case, technology that creates radio transmissions — is then evidence for intelligence.

Evidence. We’ll come back to that often in this post.

In talking about whether she believes that SETI will succeed, she calls on a quote from Christian de Duve, Life is a cosmic imperative. She says that when you hear him say that, in his serious voice with his Belgian accent, you say, Yes! I believe! But, she goes on, it’s not a question of belief. It’s about the evidence. And that, she says, is what we’re doing: we’re trying to find the evidence.

That summarizes science, at all levels — that science is about the evidence, and that when we do science what we’re doing is looking for evidence. Things like belief and hunches and guesses, however educated, serve at most as starting points for investigation. Sometimes we go into our research completely blind, not knowing where it will lead. Sometimes we have expectations, as we go in. In either case and everything between, we, as scientists, are always ready to toss aside what we expect, or believe, or hope, in favour of what we find. It’s only there that we have science.

I approach in the same way the discussion of whether people believe in evolution, or believe in global climate change. These aren’t things that one believes in or doesn’t; it’s a question of evidence. One can accept the evidence or not. In the latter case, one can give counter-evidence or reasoned arguments against its validity, or one can simply reject the evidence because of one’s beliefs. It’s that last, of course, that people generally mean when they say that they don’t believe in something scientific — that their belief systems lead them to ignore what’s observable in favour of something they believe.

During lunch, we talked about Jocelyn Bell and her discovery of the first pulsar (link to PDF of the 1968 paper). The story goes that Dr Bell (now Burnell) found slight anomalies in the data, which one would normally have attributed to minor equipment error and which would have been ignored. She did not, however, ignore it. Instead, she remembered seeing something similar in another set of data, and she chased it down, eventually finding periodicity in it.

The story points out one of the keys to science: observe, analyze, and observe again. Never stop looking for the evidence, and always be open to seeing it when it appears.

And to the real question behind the Do you believe? — does she think they’ll succeed — Dr Tarter quotes another scientist, SETI pioneer Phil Morrison, from his 1959 paper:

The probability of success is difficult to estimate, but if we never search the chance of success is zero.

1 comment:

scouter573 said...

The story of the discovery of the cosmic background radiation by Arno Penzias and Robert Wilson is much the same. They tried to make a simple measurement to calibrate their instrument (a large horn antenna). It had this odd, unexpected noise in the data, so they cleaned out all the pidgeon poop and ran the experiment again. Still this odd noise floor, so they tried to roost out any remaining pidgeons. Still this odd noise floor. They did several other things. When all other possible explanations had been eliminated, they were left with the fact that they were measuring something real - the cosmic microwave background radiation left over from the original bang. Q.E.D. Instead of fudging the data or ignoring the inconvenient data, their dedicated search for an explanation led to a Nobel Prize.