And how is this always-online node knowledge relevant when it cannot prove it is true? How will another node tell honest and liars apart? Calculate 50%+ votes?
That node itself cannot be fooled. For example, assuming that everyone is always online, the system is perfect already (under the other assumptions, of course). It's a starting point which shows that the truth can be established at least under some assumptions. Now the next question is how to relax those assumptions, to make the system more fault-tolerant, such that loss of some messages could be compensated, for instance. Etlase2 did some steps in that direction in the detailed descriptions above.Ludicrous. If everyone could see everyone in the world, then there would be no corruption due to secrets. Now how do we relax that to reality.
At this moment 6 billion people are doing something and you have no specific knowledge (but I can bet fornication is widespread).