What are some of these predictions? Probably the most unambiguous example is the dramatic effect of the indistinguishable nature of the particles on scattering probabilities. However, another example was historically more important and is more obviously essential to the qualitative properties of our universe. This has to do with atomic physics and the Pauli exclusion principle for electrons. Said principle was actually surmised from atomic physics data in the first place, and was later proved mathematically. We will simply state it.