It was recently said that anarchism might enshrine "one value above all: the autonomy of the individual."
Now, historical anarchism is a wide field. It's not a meaningless category; some things remain present, and I would say that at least one thing that is pivotal to the anarchist or the anti-authoritarian or whatever is just as the Abonilox said--the autonomy, power, sovereignty, right, or something, of the individual. Individuality is part of it, individualism is part of it.
So what rights do we have as individuals? Is there a rational basis for them?
Power, as has been said by the Nietzscheans and a myriad of ugly little rightists who think themselves supermen but who are no less correct on this point, is never to be equalized. From our musculature to our genetics to our fortune to our emotional resolve and so on, inequality seems set as part of life. For my part, I do not think this necessarily invalidates a program of political liberty and civic equality, but it does pose a challenge. Aside from right, it seems likely that power will become unequal and will be abused. Relative strength is not just a system; it is a relational dynamic.
But in Nietzsche rather than the Social Darwinists we find, amidst his perhaps unfortunate attacks on Darwin's science itself, the notion that "survival of the fittest" is plainly not true. We can point out any number of creatures who are fit but unfortunate. Komodo dragons are resilient and incredibly intelligent for reptiles; they just happen to live in some of the most volcanic islands in the world. Individuals who settled near Pompeii might sympathize. What determines fitness? Evolution is a complicated game in which many, many species are lost to valiant attempts and only a few, in times of great die-off, survive, as much due to chance as any nobility or superiority.
So it is with society, which ennobles by whim. The offspring who inherit the windfall of the mighty are not often strong enough to hold onto it, much less to have earned it in the first place. A warlike time places the most ruthless at the top; Zimbabweans may take note of Mugabe who was probably the only type of man who could have undone the rule of fascist Rhodesia. But Stalins and Saddams have great failings to match their adaptive strengths.
So it is with all strength and--intellectuals take note--all intelligence, where some gifts are useful at some times and useless at others.
So where does that leave us? It seems plain to me that there is no way to rationalize the power of some over the power of others. We all have the same right unless there is no right at all. And for me, those are the two rational starting positions, and neither is falsifiable. Either you assume equality of right because there is no grounds for advocating superiority, or you assume the amorality of all actions, as there are no grounds to articulate a moral dimension at all--save, of course, what we posit.
So it's either a Nietzschean, Stirnerian free-for-all, the war of all against all, or we'd better start working on that Heaven on Earth. Somehow I imagine that each would lead to a little of the other, whatever path we take.