The concept of hidden variables challenges traditional quantum theories by suggesting that there may be underlying factors influencing particle behavior beyond what is accounted for in standard quantum mechanics. Hidden variables would provide a deterministic explanation for phenomena currently understood as probabilistic or random in quantum theory.
According to proponents of hidden variable theories like David Bohm's pilot-wave theory or de Broglie–Bohm theory, particles have definite properties even when not observed. These properties are governed by additional parameters not included in standard quantum formalisms but could explain seemingly random outcomes predicted by conventional quantum mechanics.
If valid, hidden variables would imply that there is more to particle behavior than uncertainty and probability waves described by Schrödinger's equation. However, experimental tests like Bell's theorem have shown discrepancies between predictions based on hidden variable models and actual observations – suggesting limitations or incompleteness in these alternative explanations compared to standard quantum physics.