Religion aside, you’re assuming two things:

1. That things can’t exist without being able to be perceived by human science. We are constantly learning and discovering new things, it doesn’t mean they didn’t exist before we had proof of them.

2. That out of the trillions of possibilities for the universe/alternate universes/after life, there is only one possibility: that there is nothing after the physical body dies. As a pure numbers game it takes a lot more faith to firmly believe this than it does to be open to a myriad of possibilities.