Theory history: Submitted 2010-11-17, Doubtful 2011-03-27, Debunked 2016-01-15
Everyone Else Escaped TheoryOriginal theory: This theory assumes that the player is navigating and viewing the rooms through some sort of interface in all the games, not just in Submachine 1.
If that were true, then it's possible that whatever mechanism generates that interface (the submachine itself, Murtaugh's psychic mind-control rays, a harmless computer terminal in the Root, etc,) is also censoring out the corpses of humans. It could also be censoring out other details (obvious exits, mirrors, sub-bots, other explorers, etc,) which might prevent us from doing what the designer of the interface *wants* us to do.
Basically this theory suggests that the corpses and other obvious "missing" elements are there. We just can't see them.
Revised theory: The corpses of the missing human explorers exist within the Submachine. Someone or something, (possibly Murtaugh, possibly the submachine itself,) is preventing us from seeing them. They could be fooling our senses, editing our memories in real-time, or simply stashing the bodies where they think we won't find them.
Theory history: Submitted 2010-11-17, Debunked 2014-11-12
Natural Corpse TheoryYet another theory as to why there are no corpses. Someone pointed out to me that we have no proof that we should be seeing the corpses of other explorers within the subnet. So, taking it to the other extreme, it's possible everyone else simply found their way out like you did, and escaped.
Oh, sure, maybe they wrote a suicidal note. Maybe they complained about starving and dying of thirst. But at the end of the day, they pressed on, got lucky, found a clue, and escaped through a portal, into another section of the submachine.
At least, most of the time. There are some areas with cliffs where there's an even simpler explanation.
Theory history: Submitted 2010-11-17, Doubtful 2011-03-27, Debunked 2014-04-06
Slow Computer TheoryThe other humans who entered the submachine died, and their bodies simply decayed naturally over time. This theory works if we interpret certian events in Submachine 0 and elsewhere as implying that time travel is possible, and that some portals can and do take you backwards and forwards through time, and that how far forward or backward in time it sends you is not constant.
If this is true, then it's not too much of a leap to suppose that Mur's teams may have explored these rooms a few hundred years before the player got there, not the mere decades one would assume, then even the bones could have turned to dust by now.
This would also explain why we've never encountered a sub-bot on repair patrol. It could be hundreds of years before some matter from Earth collides with the submachine and needs to be reformatted into a patch-job that completes the circuit.
If only 20 or 30 individual humans ever entered the Submachine, then over the long course of history, it's almost unthinkable that any two travellers would cross paths. Likewise, if we assume one contiguous series of modified rooms = one repair event, there haven't been many repair jobs throughout the course of human history. (At least ones that involved collisions with habitable areas.)
Of course, one supposes that the paper the notes are printed on would bio-degrade, too...
Theory history: Submitted 2010-11-17, Debunked 2012-11-28
Original theory: There's an argument I've heard a few times when talking about AIs and Virtual Worlds, and the possibility that our own universe might be simulated on a computer which exists in a parent universe.
The argument is that if you're a Virtual Being running on a computer, it doesn't really matter to you how fast or slow the hardware is. Either way, you experience time as passing at its normal speed. It doesn't matter if you're running on a supercomputer mainframe, an old 486 processor, or an infinite number of monks working for 4 hours every alternate Friday with pencils and paper and passing around a shared abacus.
Supposing the Submachine is some sort of computer, then it's possible that any given machine within any given room within the submachine games could be treated as a logic gate. Suppose you turn a wheel, allowing steam to flow through a pipe. Congratulations, you just changed a 0 to a 1! Doors, sliding walls, live wires, they could all be treated as digital switches. Even humans moving from room to room, if detected, could be interpreted as an analog pulse.
This, to me, is the horror and the beauty of the undocumented submachine, as it existed in the days of the first experiments. The realization slowly dawned on me that I was not in a building that served any earthly purpose. That I was moving through the guts of an endless Rube Goldberg machine.
It is possible we are not prisoners or invaders of the Submachine. It is possible we are its Random Seeds, helpfully opening and closing gates in truly unpredictable manner, forming the basis for the generation of random numbers which are used by its master program.
Revised theory: Whatever function the submachine performs, the machines, pipes, and other objects within the rooms are incorporated into performing that function. When humans enter the submachine and solve puzzles, they interfere with the proper functioning of the submachine.