Arsenic-based bacterium – Real or not – it’s still science

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In earlier posts I’ve waxed lyrical about the benefits of science, as opposed to mysticism and pseudo-science. It’s detractors claim science to be just another dogma, with like-minded types falling in behind the accepted teachings. A key example raised is climate science – insinuating that the dogma is so pervasive as to explain the general acceptance of man-made climate change by the scientific community.

But this is to completely mis-understand science. Science is not a bunch of facts to be believed or not; rather it’s a process. The process is basically as follows: observe something, propose a hypothesis to explain that something, test your hypothesis, refine your hypothesis, re-test and so on. Occasionally, the testing causes us (or should cause us) to throw out the hypothesis and start again. In many cases, this process just goes on and on, continually reviewing and refining the hypothesis, until, at some point it turns into a ‘theory’.

In this context, I like to think of a theory as ‘provisional truth’. That is, it seems to describe the world quite well, but we are still open to it being falsified; that is, if something comes along which disproves the theory, then it’s back to the drawing board.

That’s why we have, for example, the ‘theory of evolution’ and the ‘theory of relativity’. These have been shown over many decades to work astoundingly well, and are therefore used as a sound basis for explaining our physical world.

And by ‘work well’, I mean two things:

  1. they have withstood testing and questioning by the community (i.e. have not been falsified), and,
  2. they have made testable predictions, which have subsequently been validated.

These two points are really a good definition of whether something qualifies as science. Try applying them to any of the pseudo-sciences, or mysticism, or religion or whatever and you will find that none of them will receive a tick in each box.

The second point is particularly interesting, since it really turns the theory into something useful. In both of those examples, we have some stunning predictions which have been validated: In evolution, the finding of the tiktaalik fossil followed a prediction that a transitional form, bridging fish and land-based tetrapods, should be found in a particular stratum (representing a period in time). In the case of general relativity, the prediction of gravitational lensing was made in the 1920’s, before being finally confirmed in 1979.

And so, to science in action: the recent announcement by NASA of the finding of a bacterium which not only eats Arsenic, but has it built into its DNA instead of Phosphorus. This has implications for the probability of life on other planets, but that’s another story. Much hoo-ha preceded this announcement by NASA, and by all accounts seemed to be solid science. There was a prediction, followed by publication in a prestigious science journal, and I heard a very persuasive interview on The Science Show last week, featuring two co-authors Felisa Wolfe-Simon, and Paul Davies (the latter being a hero of mine on subjects concerning cosmology). Incidentally, I learned that the first-named author designated the bacterium GFAJ1, which stands for ‘Get Felisa a Job’.

However, the process of science has taken hold, leading to serious questioning of the judgement of those at NASA and the journal Science. Here is a particularly scathing example, questioning both the results and the methodology.

And so, the process will continue. People will make claims, they will test them, they will publish them, and others will review and either support, or criticise accordingly.

That’s the strength of science. And if you still think that theories are only dogma, I challenge you to stop believing in that other triumph of general relativity: gravity.


2 thoughts on “Arsenic-based bacterium – Real or not – it’s still science

    Speaking of Tiktaalik… « rationalbrain said:
    December 10, 2010 at 2:55 pm

    […] of Tiktaalik… by rationalbrain on December 10, 2010 A couple of posts ago (see here), a mentioned the amazing Tiktaalik – a beautiful example of evolution at work – a […]

    […] Well here’s another claim for extra-terrestrial life, to add to our previous example. […]

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