You'll have to excuse my ignorance I am fairly new to physics, having only the sort of predegree level of maths knowledge and a few ideas. How do we come to the conclusion that baryons have 3 quarks and fermions have 2? Is there a mathematical reason for this? I assume this is proven or bourne out by experimental data too? I just remember reading that these fundemental particles come in these pairings and can see why it works as regards charge and spin but I could just as easily say there are 6 quarks or 12? Or I could say there are an infinite number of quasi quarks or they don't exist or whatever? So obviously my preposterous other theories are false, how do we maintain the ideas that there are up down down, is it something to do with the weak force? Or is there something more fundemental that leads us to this conclusion.