In a way, the conflict is the following:
A) in order to guarantee the good workings of the system, never ever, 51% of the consensus power (that is, mining power) should collude (agree on anything else but the "honest rules").
B) in order to have evolution, regularly, a very high majority of the consensus power (that is, mining power) should collude. over the change to be applied.
This can only happen if an *external* authority can define what are the "honest modifications of the honest rules", which is a select permissioned club.
I think that is not correct.
51% 'attack' - does not exist.
51% 'collusion' happens ALL THE TIME - and is what defines the current chain.
Of course. The idea is that we talk about 51% collusion if it is any deviation from the
existing rules.
If that 51% should decide on something else.. they can. The protocol simply says to follow the majority, NOT that the majority can never request upgrades, and can never change anything.
The point is the following. If you see a decentralized system as many individual entities that do not collude (that is, do not make specific agreements on anything, to do together
at a specific moment in time in a specific way) but are just running according to a given rule set (protocol), then just any small entity can join, on the condition that that entity complies with the existing rules. So that new entity can start participating at any moment, doesn't need to "make any colluding agreement with any other entity", but can just start running using the existing rule set. As such, many, many small entities can join, and they all joined using the SAME original rule set (protocol).
Of course, you can say, but "in the beginning, there was someone with >51% power, that determined this rule set !". Yes. Any such system starts out in a centralized way. Satoshi was the central authority that set up the initial rules, and of course, when he was alone, he was 100% colluding with himself. The system was entirely centralized on him. For quite a while, his self-appointed/sole/natural heirs, Core, enjoyed that continuous central power, at least "morally". Everybody used their software, so whatever they put in there, was the new rule set.
The only way new entities could join, was to accept HIS/THEIR rule set. But ideally, after a while, we have so many new entities, that the original central authority is swamped. At that point, ideally, the only thing that new entities joining could do, was to play according to the rule set that all other entities were also obliged to use when they joined.
But once IN the system, if individual entities are small, and never collude (that is, sit together, and
decide upon specific collective action at a specific moment), the only thing they can KEEP doing, is to KEEP playing according to the rules that everybody in the system had to use when joining.
That's how immutability arises from decentralisation (= the inability to decide upon specific collective action at a specific moment with majority of decision power): the impossibility to "make a collective plan of deviation" (decentralization) of the existing rule set.
Bullish to say the least.
