What the heck is meant by "Pauli force/effect"? I'm a last year physics undergrad and whenever I have a physics class given by an experimental physicist (e.g. solid state physics), they sometimes say things like "... and because of the Pauli force these two electrons are repelled ..." and whenever I enquire about what is meant, I get an answer like "it's due to the Pauli exclusion principle". But the latter only states that two fermions cannot be in exactly the same state; it says nothing about a repulsive force that acts on two fermions close to each other. In essence the Pauli exclusion principle does nothing to prevent two fermions in being arbitrarily similar states, as long as the states are not exactly the same. So what is the deal: is there an actual Pauli force additional to the Pauli exclusion principle (NB: let's not get into a semantic discussion about the word "force", call it what you will, I'm simply referring to the so-called repulsive effect of two fermions close to each other)? Or are my experimental physicis professors botching the concept of Pauli exclusion principle, making their arguments using it fallacious (i.e. there is only the Pauli exclusion principle, no repulsive effect)?