What is a theory
the nature of a scientific theory
in order to talk about the nature of the
universe and to discuss such questions as whether it has a beginning or an end
you have to be clear about what a scientific
theory is
we shall take the simple minded view that a
theory is just a model of the universe or a restricted part of it and a set of
rules that relate quantities in the model
to observations that we make it
exists only in our minds and does not have any
other reality whatever that might mean
a theory is a good theory if it satisfies two
requirements
it must
accurately describe a large class of observations on the basis of a model that
contains only a few arbitrary elements
and it must make definite predictions about
their results of future observations
for example Aristotle believed empedocles's
theory that everything was made out of four elements earth air fire and water
this was simple enough but did not make any
definite predictions
on the other hand Newton's theory of gravity
was based on an even simpler model in which bodies attracted each other with a
force that was proportional to a quantity called their mass and inversely
proportional to the square of the distance between them
yet it predicts the motions of the sun the
moon and the planets to a high degree of accuracy
any physical theory is always provisional in
the sense that it is only a hypothesis you can never prove it no matter how
many times the results of experiments agree with some theory you can never be
sure that the next time a result will not contradict the theory
on the other hand you can disprove the theory
by finding even a single observation that disagrees with the predictions of the
theory
a good
theory is characterized by the fact that it makes a number of predictions that
could in principle be disproved or falsified by observation
each time new experiments are observed to
agree with the predictions the theory survives and our confidence in it is
increased
but if ever a new observation is found to
disagree we have to abandon or modify the theory at least that is what is
supposed to happen but you can always question the competence of the person who
carried out the observation in practice what often happens is that a new theory
is devised that is really an extension of the previous theory for example very
accurate observations of the planet Mercury revealed a small difference between
its motion and the predictions of Newton's theory of gravity Einstein's general
theory of relativity predicted a slightly different motion than Newton's theory
did the fact that Einstein's predictions matched what was seen while Newton's
did not was one of the crucial confirmations of the new theory however we still
use Newton's theory for most practical purposes because the difference between
its predictions and those of general relativity is very small in the situations
that we normally deal with Newton's theory also has the great advantage that it
is much simpler to work with than Einstein's the eventual goal of science is to
provide a single theory that describes the whole universe
Was it that
I just didn't like this process was it not fast enough what was the deal with
this particular segment that I decided to not go with
