I, frequently, see people questioning what a state really is online when they see all these secessionist movements. What they're asking is could an African tribe large enough or tribes in an unwritten confederation be considered a state? Could the Ottoman Empire be considered a state? The answer is "Yes" in both the above mentioned questions.
Why do we need separate designated territories?
Some people even question whether we need a state & whether people can just live a stateless or global citizen life. For this, we need to go back to early human society. Early human society in Africa probably didn't have written laws but there was most likely a leader or leaders & their delegates (i. e. an unwritten system of governance & laws). If you were to go against the wishes of the tribe or leaders of the tribe in any way, you may be expelled from the tribe & your kin or punished for your actions. Expelled groups would go start their own tribes which would grow & become large nations of a single language (or language family of mutually intelligible languages) & identity. When these tribes (both expelled & expeller) grew into nations &, eventually, empires when competing for space - they'd frequently, almost subconsciously, hold the same resentments their ancient founding fathers held for their ancient cousins. This is why we often find nations that live next to each other having bitter resentments of the other "opposite" tribe. In other cases, we may find two groups of people "grew apart" & went to live in their own corners of the world but do not have any bitter resentments of the other because their ancient forefathers were often on good terms. It does happen that the conflict was caused by a recent action of another nation & not because of an ancient riff or peace was obtained after an ancient squabble. This is the reason people often have to obtain their own sovereign territories, it's because people quarrel & don't get along. Of course times have changed but human beings are still human beings. The thing is today, we're forced to live with tribes & nations we don't like because people are too scared to cause a change to the status quo, when changing the status quo was a norm in ancient times. Divisions in territory have been made because of language, belief systems, cultural practices etc. It is only today in the age of republics & modern countries that we have people with more in common with people from other countries than their own. In Africa, this is due to the incorrect division of tribes/nations into sovereign entities i. e. states & in other countries outside Africa, it's due to the influx of immigrants in a world where transport is efficient as ever. Humans in ancient times (& probably even today) needed separate designated territories because of differences; they needed to express their different languages, faiths or cultural practices in full in their own authority.
We keep emphasising this need to get along as if people are all the same. If a certain group of people likes violence & another group doesn't, why should these groups be forced to live in the same land? Why can't a top level meeting be held for the benefit of the groups to separate the mentioned groups into separate autonomous regions? Is that not more humane than forcing people that are constantly bickering into a single "state"? It is general commonsense that if you don't like someone, you stay away from them else the resentment make you do something you'll regret. It is claimed that wars have declined in recent times but I bet petty violence, common abuse & indistinguishable soft abuse have increased. It is better to end the riff decisively & for good than for it to constantly cause an even worse hatred by letting it continue through diplomacy. But actions to end riffs decisively have been made illegal in recent times so those who do find themselves trying to do this greater good of geographically dividing people are either ostracized or imprisoned.
I end with a quote from Italian politician, journalist, and activist for the unification of Italy, Giuseppe Mazzini, who said in 1861; "No people ever die, nor stop short upon their path, before they have achieved the ultimate aim of their existence, before having completed & fulfilled their mission. A people destined to achieve great things for the welfare of humanity must one day or another be constituted a nation (state)."