The discussion centers on the lack of evidence for white holes, with participants noting that there are no observational proofs supporting their existence. Comparisons are made to black holes, which also lack direct evidence but are inferred from gravitational effects on surrounding matter. The conversation highlights that while black holes are theorized based on general relativity, phenomena like Hawking radiation have yet to be detected. The mention of shadows, particularly a cold one on Dagobah, serves as a metaphorical point rather than a scientific argument. Overall, the consensus is that both white holes and certain aspects of black holes remain unproven in observational astronomy.