Fermions obey the exclusion principle, and they cannot be attracted to each other.
According to the exclusion principle, there must be no event that does not supervene on e while causing e*.
When electrons are squeezed too close together, the exclusion principle requires them to have different energy levels.
This is in contrast to the bosons, which do not obey the exclusion principle.
Scientist have given the name Pauli exclusion principle to this behavior.
The matter particles obey what is called Pauli's exclusion principle.
Bosons, on the other hand, do not obey the exclusion principle, and any number can exist in the same energy level.
From this it follows that they satisfy the exclusion principle.
Also, the exclusion principle prevents more than two electrons from being present in the lowest energy level.
This rule is the only visible effect of the exclusion principle in internal lines.