Symbolism, Imagery, Allegory
"Imagine not writing it all down!" Alquist exclaims (3.4). He can't believe that the scientists had only one copy of the formula for creating robots. And you know what? We just can't believe it either. Maybe that's because it's just not believable. Tens or hundreds of thousands of robots created in multiple factories for years, and the only description of how to make a robot is in Rossum's old manuscripts? Nope, nope, nope—that is silliness. Maybe it's not any sillier than creating robots in the first place—but still. It is quite silly.
Why then this silliness? Well, having the secret formula in only one place means that Helena can burn it up, leaving the robots unable to reproduce. It's a plot device—but also a thematic device. In the real world, you can't turn back technology, usually, or not without a lot of trouble.
Here, though, you can make robots, and then suddenly you can't. Helena is able to put the techno-robo-genie back in the bottle. So the secret formula, so easily destroyed, is a kind of fantasy, or dream. What if you could get rid of all this factory stuff? What if you could deindustrialize? Remember Robot Helena and Robot Primus eventually are able to love and fill the world with life, in part because no one is making robots anymore. "Only you, love, will blossom in this rubbish heap," Alquist declares (3.229). This could mean that love blossoms despite the rubbish heap, but could also mean that technology all has to go back to the rubbish heap before love gets its chance. R.U.R. is about the future, but in a lot of ways it seems to want to burn all the secret formulas as a way of getting back to a purer past.