You don't need to.
Many religions can point to a variety of miracles that have been well documented.
But since scientific method demands independent replication you simply can't consider metaphysical in scientific terms.
That just leaves out miracles. What about the weight of a soul as it leaves the body. Considering that it holds the lifetime memory of an idividual it must be very complex, it also must be made up of particles of some kind. These can be measured, the experiment would be repeatable.
String theory suggests particles can be several places at once, even belong to alternate universes. It's logical to assume heaven would be made of familiar and detectable particles. We could scan for it if we knew the particle signature of human souls.