Hi Ed
thanks for the extensive illustrations (01)
My point is simply that we cannot assume that a sound model which is
'stable' according to conventional calculus, is stable, and likely to
remain stable indefinitelyin real conditions (02)
The x factor I was suggesting means simply: assume the bridge can
become unstable
in certain conditions in the future - which is something I think
should be written on either side of the bridge. (03)
> But you cannot in any way capture in a model what you don't know
> that you don't know (04)
A model should allow for uncertainty, the product of interaction and
change, I am not sure all models of buildings do (05)
>
> >> But the surprise failures are those that involve a factor that was not
> >> considered at all, and not commonly considered in the trade.
> >> How do you build> an "X factor" defense for that? (06)
That you are trying to identify the x factor, and that is near impossible
But you can easily assume that something can go wrong and prepare for that (07)
> My experience of engineers is that there is a prevalent hubris:
> many engineers seem unable to accept that there may be something
> relevant to their work that they don't know, and cannot learn in
> an afternoon. (08)
But saying in the engineering handbook that there
> may be something relevant to a design that you don't know serves
> only to encourage intellectual humility. It doesn't provide much
> in the line of guidance. (09)
Encouraging intellectual humility is guidance, in the sense that too
many people who rely on exact science end up understimate the
fallibility of their work (010)
> (011)
> > I think we all agree that 'what is to be known' is infinite, while our
> > 'ability to know' is finite, al (012)
>
> Please note that Zadeh's work assumes that one can characterize
> sets of possible things. It does not deal with unknown concepts.
> It deals with unknown 'things' that are instances of known or
> at least postulated concepts. (013)
Yes, but that theory can be extended when we have time :-) (014)
> unless I create a class called "unidentified cosmic events" and
> estimate the possibilities of its unidentified members. (015)
yes, thats exactly what I am suggesting (016)
.
>
> Fuzziness is an unavoidable element of many aspects of hard
> science. (017)
glad to hear you say that (018)
>But the known-but-unresolved factor was analyzed,
> and new knowledge was developed. That is how science works. (019)
sometimes, sometimes it works by pure intuition of what may be there,
or not there,
at first (020)
But when they assume the validity
> of a theory as a foundation for taking the next step, they
> sometimes forget that there were unresolved issues at the edges
> of the foundational theory. And then someone with better
> measurement technology makes the critical observation and asks
> the right question. Quantum theory was born of the observation
> that, although matter and energy, as a continuum, are conserved
> in an atomic system, "spin" is not.
>
yes (021)
> We can agree to provide a list of things that we are aware may be
> related but haven't analyzed. We can agree to state the limits
> on what we were able to observe. But I don't agree that we can
> say anything meaningful about things we haven't thought of and
> can't characterize at all. (022)
we can avoid to assume that the bridge will always be stable, ie that
ta finite model will
behave constantly - thats a rather common mistake (023)
>
> The Pilgrims in New England in 1620 built a colony at the same
> latitude as Bilbao, Spain. And the first winter nearly killed
> them all, because in Bilbao the temperature does not reach -20
> and stay below freezing for weeks, but in Plymouth it did. Their
> temperature-to-latitude model was based entirely on observations
> on the European side of the gyre. How could they have known
> about the X-factor? (024)
by not overrelying on pure assumption, perhaps
> (025)
>
PDM (026)
_________________________________________________________________
Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/
To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx (027)
|