Proof-Of-Work is a Decentralized Clock
This analysis is obviously wrong, if the important thing was establishing a global clock, you could just use GPS receivers. Ordering transactions works also without proof of work, just including a hash of an existing transaction or block in a new transaction or block and this proofs the order of those transactions or blocks relative to each other. No clock required at all. And also exactly what Bitcoin does but which is totally unrelated to the proof of work.<p>I guess this has been said countless times before, but the role of proof of work is to establish a somewhat strange kind of identity among anonymous participants. If you had a trusted list of all participants, you could simply grant everyone one vote per block and decide by majority whether to accept or reject a block and get rid of the proof of work altogether. Of course using some cryptography to establish authenticity of votes and such.<p>But because Bitcoin is anonymous - or pseudonymous if you insist - there is no such list of participants and you need a mechanism to prevent participants from casting an arbitrary number of votes by essentially inventing identities. And this is what proof of work does, it limits your ability to invent identities and cast as many votes as you would like by making casting a vote really hard respectively expensive. The capital costs and the energy consumption of your warehouse full of ASIC miners become a proxy for your identity via their hashing power.<p>And that&#x27;s it, nothing more, nothing less. The rest follows from here, for example a 51 % attack is just someone using a lot of money to buy more than half of all the available identities in the Bitcoin system granting him the majority of the available votes.