From: "steve" <steve365@btinternet.com>
> > I don't see the faulty reasoning. Observation shows that most burned
> > objects are lighter than the original. This leades to the (corect)
theory
> > that something was released into the air. An (incorrect) guess was a
> common
> > substance that caused burning.
>
> Surely this is wrong. As I recall one of the things which undermined
> phlogiston was the discovery from controlled experiments that the residue
of
> a burnt object could actually weigh *more* than the original (due to the
> addition of oxygen during combustion). The response of defenders of
> phlogiston was to claim that phlogiston had negative weight i.e it weighed
> less than nothing. Shows just ho inventive people can be when trying to
> preserve a hypothesis. Steve Davies <Steve365@btinternet.com>
>
Near the end, there were believers who went to great lengths to try to keep
the phlogiston theory. However, notice what happened:
1. Scientists were faced with something they had no explanation for. (What
causes burning.)
2. Someone thinks up a theory that fits the facts. (Burnable materials
contain a substance called phlogiston that is released violently when those
materials are heated.)
3. Scientists looked at the theory to make a prediction of new facts. (If
a substance is released then the ashes should always be lighter than the
original.)
4. The prediction is tested. (The prediction is wrong, because some
materials get heavier when burned.)
5. The theory is discarded or modified. (Most people discarded it. Some
die-hards proposed that phlogiston had negative weight.)
This is exactly what a theory is supposed to do. Phlogiston was a perfectly
valid theory, based on observations. The fact that it was wrong was based
on not knowing all the facts, not on any fault of the scientists at the
time.
If it were not for the phlogiston theory's prediction that materials could
burn in a vacuum (which was shown to be incorrect), I don't think anyone
would have come up with a new theory that said the common element that
allowed burning must be available in the air.
Theories are like searching a room for lost car keys. If you find them,
great. If you don't, it wasn't a wasted search. It just tells you one more
room that doesn't have the answer.
--- Louis Newstrom louisnewstrom@home.com
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