On Nov 18, 7:04 am, James Annan <[EMAIL PROTECTED]> wrote:
> Alastair wrote:
>
> > The answer to that rhetorical question is that by arguing about these
> > matters, I do learn from the research that is necessary. Karl
> > Popper's ideas on "Falsifiability" are summarised here:
> >http://en.wikipedia.org/wiki/Falsificationism
> > where it states "Some philosophers and scientists, most notably Karl
> > Popper, have asserted that a hypothesis, proposition, or theory is
> > scientific only if it is falsifiable."
>
> Alastair,
>
> I think you (and many others, perhaps including Popper) are rather too
> literal on this. Many statements and predictions arising from the
> scientific process are unfalsifiable, even if there really is some valid
> scientific truth underlying them. One favourite example of mine is a
> weather forecast of the form "70% probability of rain tomorrow". Is it
> intrinsically unscientific to make such a forecast, since no event
> (rain/no rain) will falsify it? Note further that if someone else says
> "50% probability of rain tomorrow" then NEITHER of these predictions is
> falsifiable and indeed both forecasts might well arise from reliable and
> well-calibrated prediction systems.
>
> Going back to the paper in question, although a specific claim about
> what might have happened in the event of some different
> historical/current conditions is indeed itself strictly unfalsifiable,
> really what is being proposed is a hypothesis about the Earth's
> behaviour that may be supported or contradicted by all sorts of
> plausible analyses and observations in the future. Thus, it is entirely
> scientific in nature.
>
> At least, that is how I imagine most scientists would view the situation
> were they to think about it carefully (which some may not have done).
>
> James
I have thought for a long time that forecasts of 50% rain were
rubbish, no matter how complicated the calculations. Weather is
chaotic so it cannot be precisely calculated. But the whole matter is
more complicated than that.
Returning to the paper, if it was using a verified method (model) to
do the predictions then it could be given some credence. But at
present the climate models are unproven, and in fact can neither
reproduce the previous glaciation nor the the abrupt changes which
happened at the end of that glaciation. Crowley and Hyde claim that
their model was used to simulate Snowball Earth, but I doubt that it
exited Snowball Earth without their using a forcing of unbelievable
quantities of CO2. What I fear is that this experiment will be held
up as yet another success for the climate models when in fact it is
just a toy model suitably parametrised to give the result the authors
wanted.
The problem is that most scientists are not thinking carefully about
why the models fail. They are assuming that because the models
predict global warming and that global warming is happening then the
models are correct. But if you think carefully that does not follow.
The models could be (and are wrong i.e. wrt the melt of Arctic sea
ice) and global warming would still be happening.
Crowley and Hyde's paper may be interesting but it is just science
fiction.
Cheers, Alastair.
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