I would say that given certain prior conditions and assumptions the chance of consciousness continuing after death is actually not extremely low.
a) we are conscious now, for a seeming arbitrary reason we are conscious as a particular being and not as any other, of that we can be 100% certain
b) we don't know what the existential mode of base reality is: it is either 1) pure material unconsciousness or 2) idealistic and phenomenologically significant.
Depending on how the data of quantum mechanics are interpreted, base reality could be idealistic.
c) if 1) the basic structures of reality at the subatomic levels are non-conscious, then it needs to be explained why consciousness emerges out of the evolutionary process at some point in time. Because 'x is conscious' is a vague predicate, if you reverse engineer evolution back to the beginning of life on earth say 3.5 billion years ago, it would be arbitrary to pick a particular point in time at which consciousness doesn't exist or a particular animal or vegetable species to which consciousness/awareness cannot be applied in some form. This is the sorites paradox, which doesn't arise if 2) is assumed.
d) if we assume that before birth we never had any conscious experiences at all, that no instant of time from the big bang to the point of birth was experienced, but was just a blank nothingness, then it needs to be explained why that blank nothingness arbitrarily became filtered and siphoned off into the spacetime location of an organism resulting in a brief subjective experience within and of the universe.
e) if we assume that prior to birth we had other conscious experiences as other organisms, stretching all the way back to the beginning of time, and that even the thermodynamic error of the big bang singularity could have had a type of generic awareness, then it is less of an inexplicable datum that anyone finds themselves conscious as a personal singularity in a spacetime location.
f) until the chance of d) happening can be ascertained using relevant data, we cannot estimate the exact chance of it happening again after death.
g) a priori, d) is either the most unlikely thing imaginable (e.g. 1 in 10^20 or more all the way to numbers approaching infinity) or it is inevitable, meaning that death must necessarily be followed by other conscious experiences, perhaps in this universe (becoming conscious again as another entity which is born a second or less after death), perhaps in parallel universes or future universes (becoming conscious again perhaps in trillions of years). Whether we are born again a second or a hundred trillion trillion years after death, both will appear subjectively instantaneous.
Based on all these considerations, using rough bayesian reasoning I would say that the chance of an afterlife in the sense of continued subjective experience in some form is higher than 0, but less that 1, and could even be a 50/50 depending on how you choose to parse and combine the a)-to-g) considerations.
