Behavior and Culture in One Dimension by Waters Dennis P.;

Behavior and Culture in One Dimension by Waters Dennis P.;

Author:Waters, Dennis P.;
Language: eng
Format: epub
Publisher: Taylor & Francis Group
Published: 2021-10-15T00:00:00+00:00


6

THE CONUNDRUM OF REPLICATION1

6.1 What Is Self-Replication?

For the last three chapters we have examined how sequences function through interactors, how they actually get control of physical systems. In the language of biology, we have been studying the metabolism, the behavior, the phenotype. We have paid scant attention to reproduction, how the one-dimensional patterns in genetic sequences survive intact from generation to generation, even as their interactors perish, or how the sequences of language persist despite the mortality of their speakers.

From antiquity through the medieval period, scribes were among the most learned and respected scholars in any community. Our literate technological civilization has little use for scribes, and much of their daily work sounds to the modern ear like pure drudgery: painstakingly accurate manual reproduction of the sequences of texts. The technologies of printing, movable type, photocopying, and electronic storage have made scribes redundant; the replication of texts is inexpensive and effortless. These days if you want to witness the tedious letter-by-letter copying of sequences, the best spot to visit is a kindergarten classroom. This is where young human primates are introduced to the sequential mysteries of the “three Rs,” reading, ‘riting, and ‘rithmetic.

One-dimensional patterns are easy to copy. It is reasonable to assume that this is why the living world has settled on sequences as the scaffolding of choice for natural selection. To replicate the linear arrangement of a parent sequence to a daughter sequence, all that is needed is a rote physical mechanism, like a DNA polymerase or a photocopier or a five-year-old.

Sequences of DNA have been replicating for almost four billion years using a biochemical process common to all living things. Sequences of human speech have been around for much less time, perhaps a few hundred thousand years. They, too, are replicated using a common mechanism, the human being. But only for the last 5,000 years have technologies of literacy enabled accurate replication and archival storage of linguistic sequences. With speech your ability to replicate a sequence you have heard depends upon your memory. But with written texts, scribes can copy sequences of texts they have never seen, even of languages they do not understand, or we can deploy machines like printing presses and computers.

But we are getting ahead of ourselves. Sequences are one simple solution for replicating patterns in the natural world, but can we rule out other possibilities? It is reasonable to ask why living things don’t just replicate themselves directly, without any use of sequences at all. Replication is simple in principle; it is a kind of constraint. To reproduce an object means that the structure of one object constrains the structure of another; the original imposes boundary conditions on the duplicate.

Three-dimensional copying is easy to imagine for a stable solid object of uniform composition, such as a horseshoe. To reproduce a horseshoe, you need one machine to measure the shape and analyze the composition of the parent object and a second machine, something like a 3-D printer, to use those measurements to craft an identical daughter object.



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