According to the Wikipedia article on self-replicating machines:
René Descartes…suggested to Queen Christina of Sweden that the human body could be regarded as a machine; she responded by pointing to a clock and ordering “see to it that it reproduces offspring.”
As is clear from Wikipedia, self-replicating machines are still science fiction. The article is all about the “future development of such technology.” To better understand why construction of nontrivial, 3D self-replicating machines is so difficult, suppose we have a “model A” 3D printer that can print 3D plastic objects. This 3D printer is really a very sophisticated, high-tech machine, but it exists.
In Search of “Model B”
But now we want a “model B” 3D printer that is able to print a copy of a model A 3D printer. A 3D printer that can print anything like a model A printer is far beyond our current technology. But suppose we managed to create a model B that is able to do this. However, to be a self-replicator, the model B printer now needs to print something far more complex than a model A. It needs to print a model B; this will require a much more sophisticated, “model C” printer. Well, you get the idea. Building a fully automated factory that produces a product is difficult, but building an automated factory that could produce such factories would be far more difficult still. And to be a true self-replicator, the 3D printer or factory would have to scavenge the planet for the raw materials it requires!
Some people point to computer programs (quines) that, when executed, produce copies of themselves as examples of self-replicators. But these programs do not reproduce themselves. They only provide instructions to a computer, which, together with a compiler, operating system, and other functions, produces a copy. (Not to mention that a quine is not even a 1D machine.) If the computer could produce a copy of itself, that would be self-replication.
Behe’s “Principle of Comparative Difficulty”
In his new book, Darwin Devolves, Michael Behe offers this “principle of comparative difficulty”:
If a task that requires less effort is too difficult to accomplish, then a task that requires more effort necessarily is too.
If no one still has any detailed, workable, plan to build a self-replicating machine with the help of human intelligence — so far all we have seen is hand-waving about how it might be theoretically possible — how can we hope to come up with a scientific explanation for how one could arise by pure chance which goes beyond science fiction?
Perhaps someday scientists will build a self-replicating machine, though I am pretty sure it will not be in my lifetime, and it will not be simple. But if they do, who but a science-fiction buff could seriously believe that the errors that would inevitably arise when these machines reproduce themselves would not only not cause our “artificial species” to devolve into extinction, but would actually lead to even more sophisticated machines, though natural selection? And even if our machines somehow defy the second law of thermodynamics and reproduce themselves without significant degradation generation after generation, there is still the little problem of irreducible complexity!
Taking Reproduction for Granted
That Darwinism seems even superficially plausible depends completely on the ability of living things to reproduce themselves without significant degradation over many generations. We are so used to seeing this that Darwinists take reproduction for granted, as a natural starting point for explaining how life evolves. The video embedded below, “Conception to Birth — Visualized,” will I hope help readers to appreciate how astonishing, how “unnatural,” reproduction really is. “How do these instruction sets not make mistakes as they build what is us?” asks mathematician Alexander Tsiaras.
If intelligent humans ever design self-replicating machines, that will certainly still not explain how life could arise through chance, or how it could become even more complex over the ages through duplication errors. But until engineers can design clocks that produce offspring reliably generation after generation, all scientific explanations for how life arose and evolved should be seen as what they are: pure science fiction.
Update: About the photo above, note that despite the claims made by the manufacturer that this is the “3D printer that can print itself,” it only prints the plastic components, and “other components, such as steel rods, nuts and bolts, motors and separate electronic components, would be supplied externally,” as the Wikipedia article states. Of course it does not print the computer shown between printers, which is where the hard work is done. And by the way, humans supply the raw materials and assemble even the plastic components!
Photo source: Wikimedia Commons.