[anon987]

"When used as a failure detector, timeouts are just a guess that something is wrong."

I send a packet over the network. I configured the timeout to be 10 seconds. 10 seconds passes. Is the packet truly lost? Or, maybe the packet was received, processed, and and a response is on the way back, but it takes 20 seconds instead of 10! Or maybe it takes an hour instead of 20 seconds. Or a decade.

We don't know if the packet is truly lost or is just taking >$timeout_timer and making assumptions is dangerous.

[sdab]

My question was about his claim in regards to the result in the paper. In practice, you are right but a consensus algorithm is still "partially correct" if it never decides on a value. It is only incorrect if different nodes decide on different values. For example, paxos does is not guaranteed to decide on a value. So timeouts are useful guessing tools, but I dont see how there is no consensus possible without them.