I&#x27;m saying that these quarks are not long-lived, they come and go like other virtual particles.<p>You have this behavior outside of a hadron too, just that you&#x27;re more likely to see a quark-antiquark pair inside a hadron than outside. The sea quarks within the hadron are still virtual particles, though.<p>And often virtual particles aren&#x27;t considered to be there at all, after all, from that logic one might say that a proton contains all particles (it does, since there always is  a possibility of a virtual particle pair of any type springing up). Of course, the possibility of the quarks coming up is more likely since they can be obtained from a gluon, but they&#x27;re still virtual.<p>We&#x27;re just dancing around the question &quot;should we count virtual particles when talking about the contents?&quot;. The answer usually depends on context. So it&#x27;s completely ok to say that a proton is just three quarks, since those are the only real particles in it.