D&C 131:7-8:
7 There is no such thing as immaterial matter. All spirit is matter, but it is more fine or pure, and can only be discerned by purer eyes;
8 We cannot see it; but when our bodies are purified we shall see that it is all matter.
Mormon doctrine asserts that there is a form of matter, invisible but not in principle undetectable, that interacts with normal matter. This matter is somehow related to the persistence of memory and personality beyond death, and also plays into agency and qualia.
We already know of dark matter, which interacts with visible matter only gravitationally and comprises a whopping 96% of the matter in the universe. Direct evidence for dark matter was announced only three years ago. Two large clusters of galaxies collided, and the dark matter traveled farther than the visible matter: while both forms of matter responded to gravity, the visible matter was also impeded by electromagnetic forces between the hot gasses. The dark matter, now stripped of normal matter, was detected by gravitational lensing.
Around the same time a new technique was proposed that would allow us to image anything that gravitates. For the first 400 thousand years after the Big Bang, the entire universe was glowing. Once the hydrogen cooled to the point that it was not radiating, the universe went dark. Around 400 million years after the Big Bang, starts started to form and there was visible light again. For a while before the stars lit up and for a long time thereafter, nearly all light in the universe was 21 cm light, the Lyman-
So dark matter is one candidate for spirit. There are several different ideas about ways dark matter could arise and what it might be made of; the properties of dark matter besides gravitational interaction vary widely from one proposal to the next. I don’t know if any of the proposals would allow for the necessary complex localized systems akin to bodies and minds to form, but it’s not unbelievable that dark matter could support such systems.
However, one thing everyone expects is that dark matter will obey laws that are very close to what we’ve already discovered; after all, we have proof that dark matter responds to gravity in the same way as normal matter. It will form linear superpositions of states, conserve energy and momentum, not violate causality, and so forth.
Most importantly, there’s no reason to believe that it will be any less ‘mechanical’ than the matter we already see around us, no reason to believe that there’s some property of dark matter necessary for qualia and agency. So while it may be the case that human minds depend on dark matter for their conscious experience, there’s no a priori theological reason we couldn’t build a perceiving machine.
We now come to the dancing pixies problem. Consider the quantum state of a perceiving being; we can write it as a weighted sum of basis states. Decoherence provides a preferred basis, usually consisting of states that are narrow in both position and momentum, but there is some evidence that quantum superpositions might persist in the brain. However, if it is simply the relative weights of the basis vectors that constitute a perception, then perceptive states arise by accident all the time. This is known as “panpsychism“, a strong form of animism. If one accepts this worldview, then because many (most?) of these states must be experiencing pain, this has bearing on the Atonement: will it bring about a universe in which accidental pain-perceptive states are forbidden?
Perception, however, is necessarily embedded in time. The computationalist says it is not the states that perceive, but rather the computation leading between the states. Naively, one might think that nothing has been solved: surely it was a physical process leading between the states previously identified as perceptive above. However, in computer science there is the notion of equivalence classes of computations: two programs may give the same output on each input and yet be fundamentally different programs. This is, essentially, the point of the Chinese room thought experiment.
The principle of relativity suggests to me, however, that bisimilar systems should be considered equivalent with respect to perception. Two systems are bisimilar if they each simulate the other: given an arbitary state of the first system, you can compute the state of the second system and vice-versa, and that relationship is preserved under time evolution. So an arbitrary physical process leading between states corresponding to successive states of a perceiving brain does not necessarily perceive, but a faithful simulation of the processes in the brain should.
