Tagore argues that truth and beauty are not independent of humanity but are realized through the human mind; what we call truth lies in the rational harmony between the subjective and objective aspects of reality, both of which belong to the universal human. Reality apart from a perceiving consciousness has no meaning we can access.
Einstein holds that there is a reality independent of the human mind, and that scientific truth must be conceived as valid whether or not any human observes it. He concedes he cannot prove this position, calling it a faith no scientific method can dislodge or establish.
In their 1930 Berlin conversation, Einstein pressed the question with a concrete test: does a table exist when no one is in the room? Tagore answered that its existence still depends on a universal, not individual, human consciousness, while Einstein insisted the table's reality is independent of any mind, leaving the two unable to agree.
Tagore distinguishes the individual mind from a 'Universal Man' or collective human consciousness; truth and beauty are relative to this universal human rather than to any single person's perception. This lets him claim truth is human-dependent without making it merely private or arbitrary.