Final answer:
Objects in the physical world cannot be the source of true knowledge because true knowledge is based on empirical evidence and the physical world can only provide limited sensory experiences. Materialism, which limits knowledge to what can be empirically verified, cannot account for non-physical or spiritual entities.
Step-by-step explanation:
Objects in the physical world cannot be the source of true knowledge because true knowledge is based on empirical evidence and the physical world can only provide limited sensory experiences. Materialism, which limits knowledge to what can be empirically verified, cannot account for non-physical or spiritual entities. Additionally, knowledge of the external world is limited by our own perceptions and the problem of verifying anything outside of the realm of thought. While we can understand and analyze objects in the physical universe, their true nature and the existence of non-physical entities are unknowable.