Here's how I look at the question of whether a bit string, if accidentally implemented as part of another program, would be conscious.
First, it's a little confusing what we mean by a bit string. Is this the program of the computer? A snapshot of its state? Can a program or a snapshot be conscious? Suppose that instead of talking about a bit string, we consider instead the actual sequence of states that the computer goes through. Then we could ask, if this sequence of states matched the sequence of states that was part of a conscious program, but in this case they happened accidentally as part of some other program, would they nevertheless create a consciousness? Second, even with this definition, it's an unreasonable question. That is, given what we know about the complexity of consciousness, it doesn't make sense that a computer could accidentally run a program that matched the run of a conscious simulation, for a long enough period that it would correspond to a perceptible moment of consciousness. The brain has something like 10^12 neurons and 10^15 synapses, and they'd probably have to be simulated at microsecond resolution (if not a million times smaller) to get a simulation that was at all accurate. This means that there would probably be something like 10^23 bits of information in a simulation of a tenth of a second of a human brain, if you capture all of the connectivity and timing information. There's no way that you could accidentally match a 10^23 bit pattern in this universe. Even if every sub-atomic particle in the observable universe were a computer, you'd be hard pressed to match even a 300 bit pattern by accident. The additional difficulty for the accidental match of a brain pattern is so much greater that our minds can't even conceive of how impossible it is. Third, even though it will never happen in our universe, if we believe in the multiverse then we have to admit that it will happen by accident, somewhere. So we might still want to answer the question of whether this accidental instantiation of the computation is conscious. I would approach this from the Schmidhuber perspective that all programs exist and run, in a Platonic sense, and this creates all computable universes. Some programs create universes like ours, which have conscious entities. Other programs create random universes, which may, through sheer outlandish luck, instantiate patterns which match those of conscious entities. All consciousnesses exist in this model, and as Bruno emphasizes, from the inside there is no way to know which program instantiated you. In fact this may not even be a meaningful question. But what are meaningful to ask, in the Schmidhuber sense, are two things. First, what is the measure of your consciousness: how likely are you to exist? And second, among all of the instantiations of your consciousness in all the universes, how much of your measure does each one contribute? This, then, is how I would approach the question. Not, is this accidental instantiation conscious; but rather, how much measure do such accidental instantiations contribute, compared to non-accidental ones like those we see in the universe around us? I suggest that the answer is that accidental instantiations only contribute an infinitesimal amount, compared to the contributions of universes like ours. Our universe appears to have extremely simple physical laws and initial conditions. Yet it formed complex matter and chemistry which allowed life to evolve and consciousness to develop. Maybe we got some lucky breaks; the universe doesn't seem particularly fecund as far as we can tell, but conscious life did happen. The odds against it were not, as in the case of accidental instantiation, an exponential of an astronomical number. This means that the contribution to a consciousness from a lawful universe like the one we observe is almost infinitely greater than the contribution from accidental instantiations. Therefore, I would suggest that the answer to the question of whether an accidental instantiation is conscious is simply this: it doesn't matter. Even if it is conscious, its contribution to the measure of that conscious experience is so small as to be completely negligible. Hal Finney