In further studies, we were able to use reactions employing the isotopically chiral initiator at lower and lower ee values to probe the threshold imbalance of product enantiomers that is required to ensure that the chiral amplification proceeds via the stereochemical direction dictated by this imbalance rather than stochastically. Together with stochastic kinetic modeling incorporating the role of stochastic noise, we determined that the threshold autocatalyst ee value to escape stochastic behavior lies between 3.5 x 10 -7 -3.5 x 10 -8 %ee. Soai had reported that the reaction began to show inconsistent results when the reaction product was employed at values below 10 -5 %ee, presumably hampered by either inevitable inaccuracies in the measurement or the presence of cryptochiral impurities. The fact that Soai's ee measurement is two to three orders of magnitude higher than the calculated threshold highlights the challenges inherent in accurately and reproducibly carrying out experiments employing such small differences in enantiomer concentrations. Scheme 10. Simplified mechanism of asymmetric amplification in autocatalysis in the presence of chiral initiator (green triangles) that forms complexes with reaction product (blue and red block arrows) produced in the background reaction. Slightly higher stability of the complex formed between the R initiator and the S product results in a slight excess in free R product, which then becomes amplified in the ensuing autocatalytic cycles Reactants not shown for clarity. Inset graph shows an experimental kinetic profile from in-situ monitoring of the Soai reaction. This estimation of the threshold ee value required for faithful direction of the Soai reaction also allows us to estimate that the energy required to break symmetry with a consistent chiral bias lies between 1.5 x10 -7 -1.5 x 10 -8 kJ/mol. This value may in turn be compared to the best current best estimates for parity-violation energy difference, PVED, caused by asymmetry in the weak force, which lies five to seven orders of magnitude smaller than our energy estimate. This result may appear to cast doubt on whether the initial chiral selection could have arisen from PVED under the conditions of an amplifying autocatalytic reaction. While we cannot discount PVED as the original source of chiral symmetry breaking, our work provides context for any autocatalytic reaction scenario invoking PVED in symmetry breaking. It is likely that on the time and volume scales of feasible laboratory experiments, this minute energy difference will be lost in the stochastic noise of any autocatalytic network exhibiting the kinetic features of the Soai reaction. It is thus highly unlikely that an experimental observation of PVEDinduced symmetry breaking will be observed in Soai autocatalysis.