[dragonwriter]

> Does a ‘physical clock’ with sufficiently accurate inter-node synchronisation and sufficiently good time resolution not meet the ‘logical clock’ definition?

No, because a logical clock is a clock that is logically guaranteed to capture (I would prefer “bound”, but “capture” is the article’s term) causality, while a physical clock may or may not happen to do so with sufficient synchronization and resolution, but this is (unless I misunderstand) impossible to verify as a necessary condition regardless of how good the clock is.

[vlovich123]

In practice though, physical clocks can actually provide such good bounds that you can start to not care about the distinction. That’s why you see Google using GPS clocks for their global database to really great results. NTP doesn’t cut it. Atomic clocks could be even better but they have distribution challenges that GPS drastically cuts down on.

[jacksonkmarley]

Ok, that's a good point, the word 'capture' might have been the issue, I would have said that the logical clock idea guarantees causal order then. I guess that is what the article is saying.