Re: A thought experiment...
- From: Jonathan Thiessen <jjthiessen@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 01 Mar 2007 03:57:56 -0500
Puppet_Sock wrote:
On Feb 27, 12:53 am, Jonathan Thiessen
<jjthies...@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Puppet_Sock wrote:On Feb 25, 5:09 pm, Jonathan ThiessenThe point of proof by contradiction is to assume something false, follow
<jjthies...@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
[snip]
A.1: Assume that the Universe has always existed [ie anThis sure seems to be a problem. Ever heard of the Big Bang?
indefinite/infinite amount of time has already lapsed]
Look it up.
through with correct logic, and arrive at something which is clearly
false, thus proving that there was in fact something wrong with one of
your original assumptions.
Um. No. The point of proof by contradiction is to assume
something, show it leads to a contradiction, and thus show
that it is false.
I don't see any conflicts between our descriptions. Please note that I said "to assume something false", _not_ "to assume something _is_ false". I suppose that it was somewhat superfluous to state that the assumption is false [it's just that it won't work if all of your assumptions are correct [Of course, you needn't really know that validity of an assumption to try proof by contradiction, it's just that you may not really get anywhere with it]].
Assuming things that are contradictory to observation is
pretty pointless. Imagine assuming that horses were
made of perfectly elastic material, then observing that
they don't bounce. The conclusion is *not* that horses
have an attitude about bouncing.
I wasn't sure on what all is generally accepted, hence the attempt of "proving" finite existence. The actual proof was regarding finite existence. The rest that followed was an aside discussing implications/results. I suppose it would have been better format to keep discussion even more separate [a different post], or try formulate it like a [semi]formal proof that relies on/references finite existence.
When you get into regions beyond the observtions, you
need to be pretty careful about making strong conclusions.
For sure.
There are alternative notions as to what happened to get usI see... Could you point me in the right direction [Possibly a good
to a non-heat death situation. None of them is right now
ascendant, as we do not have any significant data to
decide between them.
introductory article].
You could do worse than open a cosmology text.
I seem to recall Asimov having written an intro
text on the topic. It would be from some decades
ago, but it would be easy to read.
The wiki article is kind of fluffy, what with dragging
in all kinds of things about ancient mystical explantions
of the origin of the universe.
http://en.wikipedia.org/wiki/Cosmology
But it's a trend in cosmology that is at least as old
as Sagan's series _Cosmos_. Just remember my
rule about references and textbooks. Don't read
just one. Read as many as your time, money, and
stamina allow you to read.
Look for topics like:
- heat death of the universe
- steady state universe
- pulsating universe
Socks
Thanks for the leads. I've started looking into it a little bit, but probably won't get too much time to go too deep until the summer [passing is good]. Anyway... Have a good one ;)
.
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