My understanding of what allows me to touch, say, a desk is that the desk electrons become very near the electrons on my hand and the electric force repels them. However, if I have 2 electrically neutral particles, such as neutrons, why do they not just pass through each other or something? My best guess would be that the neutrons are made up of quarks which do carry charge. It is actually that the quarks are getting near each other and repelling. The neutron itself is electrically neutral only in total. If this is the case, what if I took a neutrino, and fired it at another neutrino. I'm not exactly sure what a neutrino is, but would they not occupy the same physical space at an instant?