Hard Problem of Scientific Evidence

The problem of underdetermination: For any given body of scientific evidence, there are always multiple, logically possible theories that can explain it equally well. Data alone cannot force us to choose one theory over another; extra-scientific criteria like simplicity, elegance, or compatibility with other established theories (paradigm loyalty) must be used. The hard problem is that these criteria are aesthetic and pragmatic, not purely empirical. Thus, the move from evidence to theory is never a strict logical deduction, but a creative, sometimes subjective, leap.

Example: Centuries of astronomical evidence (planetary motions) could be explained perfectly by either Ptolemy's complex earth-centered model (with epicycles) or Copernicus's simpler sun-centered model. The evidence alone didn't decide. The choice was made based on the principle of parsimony (simplicity), which is a philosophical preference, not a law of nature. Today, the weird results of quantum experiments are explained by both the Copenhagen interpretation and the Many-Worlds interpretation. The evidence fits both; our choice is a matter of metaphysical taste, not evidential compulsion. Hard Problem of Scientific Evidence.

Hard Problem of Scientific Evidence by Enkigal January 24, 2026