Complex sentence: However, we can intersubjectively verify that people almost universally experience discomfort (hunger) when they haven't had enough to eat, though we generally have only a crude ability to ascertain or compare (measure) internal experiences.
Split into simpler sentences: However, we can intersubjectively verify that people almost universally experience discomfort (hunger) when they haven't had enough to eat. We generally have only a crude ability to compare (measure) internal experiences.