Rowhammer of God

You may have heard that “we are probably ‘living in’ a simulation”. The conceit is that any species that both develops sophisticated science and avoids the depressing solutions to Fermi’s Paradox will inevitably develop vast computational abilities. Thus, they will be able to simulate entire universes at the physical level, including conscious entities such as themselves. With sufficient fidelity, this consciousness will be “real”. Given that even one such species would be able to simulate untold quantities of universes with conscious entities, the vast majority of conscious entities in the universe “must” be simulated ones. If this kind of speculation amuses you, I recommend reading Neal Stephenson’s novel Fall. If you choose to do that, you will thank (for values of “thank” that may include “curse”) me if you first read his Cryptonomicon and System of the World (why? Three syllables: Enoch Root). Most of the discussions of this topic that I have seen assume that we could never, by definition, determine whether we are simulations. Various objections to this assumption exist such as “all simulations are code; all code has bugs, find the bugs, prove the simulation”. I prefer a more constructive approach to objection.

Now let us discuss e-ink. Its crisp black and white display comprises pixels, each a tiny sphere, half black, half white. Each sphere can be flipped so that either the black half or the white half is showing, providing a programmable monochrome display. These pixels are quite large compared to the nodes laid down on today’s integrated circuits. I challenge you to imagine various possibilities here: nano-traces could be written on the surface of the pixel-spheres, each its own microprocessor; instead of spheres use tiny cubes (or other polyhedra), each face a different color; make them even tinier and faster, for high-res videos.

As you know, computers are “merely” bunches of networks of electrical circuitry. A memory bit is essentially a tiny volume of electrical field held steady and controlled by clever arrangements of matter. These tiny volumes are jammed so tight you’d think they would interfere with each other, but part of the cleverness is arranging things so that they are immune to the expected proximity effects. However, if a programmer arranges for, say, a whole bunch of bits surrounding a target bit to flip between one and zero according to some clever pattern, it is possible to force that target bit to flip, independently of the normal control mechanisms. This is known as a rowhammer attack. Similarly, you might recall famous stories, from the olden days of computing, about how clever patterns of reads and writes on one of those refrigerator-sized disk drive cabinets could exploit natural resonances of the system, so as to “walk” the drive across the room.

Now, any computer running a simulation of us is going to have to compute whatever we do convincingly enough that it matches our understanding of our simulated physics. If we can impose excess load or complexity, or exploit the equivalent of resonances in the apparatus, the outcome would appear to us either as new physics or the supernatural. Who knows what it would take, maybe cubic light years of arrays of quantum dot e-ink screens playing random cat videos. The basic idea behind these rowhammer and disk drive antics is that no physical system, as we conceive of physics, is immune to clever interventions. I recall certain dialogs from Hofstadter’s Gödel, Escher, Bach, where the Tortoise repeatedly disassembles Achilles’ ever-more-sophisticated record players with carefully crafted platters. Let’s just hope the alien Sim-Universe players don’t reset to an earlier save if their computer room starts shaking.