Logic and evolution: the giraffe problem (Introduction)

by David Turell , Tuesday, January 15, 2019, 17:42 (2137 days ago) @ dhw

DAVID: From the article: "the amoeba just reacts passively to the conditions" and reacts automatically.

dhw: It can’t change the conditions, can it? But why are you rewriting the sentence? It continues: “…and figures out the best possible arrangement by itself” – the exact opposite of “reacts automatically”.

DAVID: By itself of course can mean automatically. It only reacts to light or food as the article says.

dhw: Why do you keep ignoring the words “figures it out by itself” – that can’t mean automatically!

Because that is exactly where the authors offer an opinion not based on their description of the slime mold's abilities 'reacting passively'. One cannot have it both ways, or perhaps you want them to.

DAVID: Quote from article: " Physarum polycephalum is a very simple organism that does two things: it moves toward food and it moves away from light. Millions of years of evolution has made Physarum abnormally efficient at both of these things." Where do you see intelligence???

dhw: Unfortunately, something went wrong with your reproduction of the article: several paragraphs were repeated and the account of the experiment itself seemed incomplete. I’ve checked and the missing section reads as follows:

“In this particular case, each channel represents a city on our hypothetical salesman’s route, along with the order that the city should be visited (dhw: i.e. there is food at the end of each channel.) When the amoeba extends into a channel representing a city, it affects the likelihood that a light will go off in channels representing the next cities on the route. The further away the city is, the more frequently the light will go off in that channel.”

You then gave us the following quotes: 'The mechanism by which the amoeba maintains the quality of the approximate solution, that is, the short route length, remains a mystery….But if the researchers can figure out just how the amoeba works [..] It could speed up our ability to solve all kinds of difficult computational problems and change the way we approach security.
"This one small amoeba—and the way it solves difficult problems—might just change the face of computing forever."

I’m not sure I understand all of this, but you obviously did and called it “amazing work”, and you also used the word “amazing” in your heading. Mere automaticity is hardly amazing. We needn’t dwell on it. I’ll stick with McLintock, Margulis, Buehler and Shapiro if you prefer.

The amoeba works like the bi-digital programming of 01 or 10. It is either yes or no at each channel. The amoeba can only reacts to food or light. That is automatic. What is puzzling is the mechanism whereby the amoeba chooses to react or not. That obviously can be automatic
based on strength of signal, accept or ignore, still yes/no programming.