Hello. Obviously I have only an amateur understanding of physics, but I am trying to gain a bit more knowledge about the concept of quantum spin. I understand that 'spin' does not refer exactly to angular momentum, but I believe more to a kind of mathematical degree of freedom which has similar properties to intrinsic angular momentum. But I was wondering if there is more to concept of spin than this in our understanding. As wikipedia says: "As the name indicates, the spin has originally been thought of as a rotation of particles around their own axis. This picture is correct insofar as spins obey the same mathematical laws as do quantized angular momenta." How can an indivisible point rotate? Also on wikipedia it claims Richard Feynman made this statement about spin when asked for a layman explanation: "What he said was that groups of particles with spin 1/2 "repel", whereas groups with integer spin "clump"" I don't really understand this, as don't groups of fermions, like electrons, repel one another because of their like charge. What approximately did he mean by this? Thank you.