Nick Szabo  🔑

Knowing makes you less vulnerable if you have the capability to respond, e.g. by finding other correct nodes and maintaining your own un-attacked fork.

But there is nothing invalid about a chain that has been re-orged, miners will be economically incentivised to mine on the longest (re-orged) chain.

Right, knowing about a 51% attack doesn’t change anything. Miners are not required by consensus rules to build on the blocks of other miners.

I am not sure what you are trying to say here but miners are incentivised to mine on the longest (valid chain) to decrease the likelyhood of their blocks being orphaned

Assuming that incentives will make people do the right thing is still an assumption. Without full nodes to hold minors accountable that incentive goes away.

Agreed. I am talking about what security diffs a full node vs an SPV node has for an individual actor, not under the assumption that everyone runs SPV. The valid chain is the chain with the most difficulty that still complies with protocol rules.

And an SPV wallet cannot know the rules have been satisfied and therefore cannot know if it is following the chain at all.

Agreed. I am not at all arguing that spv clients can determine whether or not blocks are following the inflation shedule. I am arguing that under the conditions necessary for a miner to inflate the supply like that, a re-org attack can be also done which affects both node types.