Expt & theory (was Separation of science and religion)

George Murphy (gmurphy@raex.com)
Mon, 24 Nov 1997 12:34:13 -0500

Richard Dimery wrote:
> > Theory may suggest what experiments to do but experimental science is indeed
> > theory free. Experimental science is constituted by historical propositions
> > of the type: "on such and such a day I released the stone and it fall as
> > follows." The generalization of such events constitutes the laws of
> > (experimental) science. The interpretation or understanding of the laws
> > constitutes theory.
> Even data, I'm afraid, is often seen as theory-laden. There is some
> interpretation going on even when we report things. If you talk about a
> stone going through a glass window, you're making assumptions about the
> state and nature of the glass before and after the event, talking about
> properties of glass containing counterfactuals (unbroken glass is fragile,
> meaning that _if_ it were to have a stone thrown at it, it _would_ break.)
> You're classifying "glass windows" as transparent sheets made of a
> category of compounds based on aggregate. You're assuming your eyes aren't
> deceiving you, and the stone isn't just passing through the glass.
> Even needles flickering on electronic equipment are theory-laden
> observations. We don't just say "oh, the ammeter needle is moving 30
> degrees. That's interesting". We say "oh look, there are 4.5 amps moving
> thorugh that wire" (excuse my physics). Our observations generally have an
> extra layer of interpretation even before we start to Interpret them.

I agree. Even very simple observations require some theory.
E.g., an astronomer reporting positions of stars has to assume
rectilinear propagation of light in a vacuum (in addition to the usual
corrections for atmospheric refraction &c). & the farther our
experiments & observations get from everyday experience - with
elementary particle physics e.g. - the data become even more
theory-laden. This doesn't mean that the discovery of things like
quarks is pure "construction" as some post-modernists would say, but it
does mean that there must be feedback between theory & experiment, &
that the two can only advance together.
George Murphy