Scientists working with physical evidences see as reliable that data which can be replicated and verified by others. We call it "objective empiricism".
Might we not admit to a "subjective empiricism" wherein experiences of the mind and spirit are replicated and verified by others?
Just as precise laws govern matter and energy so are there laws governing in the spiritual realm. We find that careful observance of these as guidelines yields verifiable evidence with all assurance.
It is interesting to note that one having devoted much if not all one’s life to the objective will, now and then, recognize the subjective and with deep satisfaction find it also valid and real.
Remembering the song, "Amazing grace" we find the phrase, "I was blind but now I see".