It seems axiomatic that each clearly distinguishable national group should have the right to self-determination. But, it may not be as simple as that. As an Israeli it seems clear to me that both the Catalans and the Kurds deserve the right to self-determination They both have the basic requirements, they have an existing governmental organization that is both working and somewhat transparent, they have a distinct language and culture and they have the means to defend themselves. At least the Kurds do, their Pesh Merga forces have been the most effective at fighting IS and they are the main US ally in Iraq.
So I was disconcerted when I read a letter in The Jerusalem Post (from an Arab) saying that if Israel supports self-determination for the Kurds, why not for the Palestinians. At first sight this might seem a reasonable comparison, but then you see that it clearly breaks down. The Palestinians do not have a distinct language or culture that is distinguishable from the Arabs living around them (say in Jordan and Syria), they do not have an effective governmental organization, and they do not have the means to defend their territory if they were independent.
But, perhaps more important, they are not really a distinct people, their “independence” was first declared by the PLO (an organization that was founded by the Egyptian secret service) in 1964, just prior to the 1967 Six Day War. Whereas the Catalans and the Kurds have truly ancient origins. Catalonia was conquered by the Spanish Castilians in medieval times when Spain was first unified and the Kurds were conquered and divided between Turkey, Syria, Iraq and Iran, and in fact are considered the largest minority without a sovereign country of their own.
So just because you can name a group does not mean that they deserve self-determination or in fact could achieve it. It will not be easy for the Catalans and the Kurds to gain their independence against the opposition of the Spanish State and the Turks and Iraqis, respectively. Furthermore, there are many minorities whose independence cannot be foreseen, such as the indigenous Americans (Indians), the Welsh, the Bretons, the Chechnians, the Ossetians, the Maoris, the Australian Aborigines, Irian Jaya (the part of New Guinea taken over by Indonesia), Kashmir and the Palestinian Arabs.