It is a logical conundrum that Mormonism accomodates by various ex post rationalizations. Socialization within the church reinforces this belief regularly. To equate personal revelation with science is a false comparison. Science moves forward because it is verifiable. It is testable.
Different persons applying the same methods reach the exact same results.
If I make a scientific claim, my claim is only accepted if it is replicated and validated by others. Absent this, my claim does not stand. And, the methods used to test claims are objective, transparent, and replicable. Note that NONE of this applies to claims of spiritual witness. They are not testable.