[Right Wing Professor]

By this argument, a camera is a Turing machine; it reads in data as light, and outputs it as exposed film. For that matter, an object sitting in a sunbeam creates a two-dimensional projection of itself as a shadow on the floor. A crystal growing in a solution is a Turing machine; it reads an arrangement of atoms on a surface and deposits successive layers identical to or complementary to the previous one. Since we know a crystal can grow purely by the laws of nature, that a shadow is cast because of very simple optical principles, it's hard to see what this very broad defintion of a Turing machine proves.

[Southack]

"By this argument, a camera is a Turing machine; it reads in data as light, and outputs it as exposed film. For that matter, an object sitting in a sunbeam creates a two-dimensional projection of itself as a shadow on the floor. A crystal growing in a solution is a Turing machine"

That's utter nonsense! Shame on you Professor, you of all people should know better!

Tsk, tsk, tsk...

Writing to the same tape or writing to a different tape based upon processing commands is NOT equivilent to an expressive, template-style system such as a photocopier (an example that I EXPLICITLY used above in this thread to head off precisely the sort of gaming that you are now engaging in) or a camera.

A DNA system (or cellular system, if you must) processes commands/data and alters its output based upon those commands/data. Turn off a gene with a new command, and the DNA system processing said gene but does not execute the rest of the gene's internal code (but as I've already noted - gee this is getting tiring, especially when dealing with people who should know better - as I've ALREADY noted, an expressive template system will copy something blindly - to turn off part of a template one must overwrite it, erase it, or delete it in that sort of system - ala a photocopier or camera).