Re: General semantics

On May 20, 9:24 am, Gene Wirchenko <ge..._at_ocis.net> wrote:
> On Wed, 19 May 2010 18:54:45 -0700 (PDT), Tegiri Nenashi
>
> <tegirinena..._at_gmail.com> wrote:
> >On May 19, 5:22 pm, paul c <toledobythe..._at_oohay.ac> wrote:
> >> ... The message I got from the book, at least the practical conclusion, is
> >> that we must always think separately about a system and reality, ...
>
> >This is a recurring theme in many science endeavors. I remember a
> >story told by prof Mark Krasnoselski (RIP). "Here is a linear dynamic
> >system with a simple positive lookback. It converts an input  x(t)
> >into x(t-T). Think about it: it predicts the future! When this has
> >been discovered many "hands-on" people rushed to make actual
> >implementations! Than he paused.... Do you understand the difference
> >between the model and reality?"
>
>      Could you please unpack this?  I do not have the background to
> follow the story, but I understand the conclusion.

Not sure what you are asking. The background http://www.stanford.edu/class/ee102a/lecture4x4.pdf It studies systems assembled out of well defined primitive blocks such as delay, integrator, differentiator, etc. I don't remember the detail of the system in question, other than it contained a no more than two elements arranged in a simple feedback loop and one of them was delay. One reason why it doesn't work as intended is because it is unstable. Received on Thu May 20 2010 - 22:52:24 CEST