[dylkil]

if a non mining node decides a block is invalid it will fork onto its own chain. If no mining nodes start mining on this forked chain then the original node is left on a chain where no transactions can be processed.

Non-mining nodes have no power or influence over the networks state. It is the mining nodes who decide which chain lives and which chain dies.

[jude-]

Non-mining nodes are still responsible for storing and relaying blocks. If no one stores and relays your block, was it ever mined?

[dylkil]

Remove the non-mining nodes from the network and the node count goes down, but the network security stays the same. Non mining nodes do nothing for the security of the bitcoin network.

Having more non mining nodes to store and relay blocks is beneficial to decentralization, but they have no influence over which chain becomes the longest chain.

[jude-]

I'm sorry, but this is simply not true. Bitcoin's security is ultimately underpinned by each node being able to independently validate the chainstate. If nodes couldn't be guaranteed to receive all blocks on the best fork -- a task fulfilled not by miners, but by the continued availability of non-mining nodes that store and relay blocks -- then not only would miners be unable to build a high-quality chain (since they would have a hard time receiving each other's blocks), but also it would be much easier to eclipse nodes and/or feed them a valid but lower-quality chain that they would be unable to determine is the globally-best chain.

Also, block validity includes more than just proof-of-work. Each node ultimately decides which block it accepts or rejects. The protocol defines the minimum criteria for a block to be valid, but each node may independently apply additional criteria that must be met. If all nodes decide to reject a protocol-valid block that a miner produces, then the block will be orphaned -- it won't matter how many descendant blocks get built on it, because the rest of the network will ignore them all. In fact, this is the mechanism by which a user-activated soft fork works [1].

[1] https://en.bitcoin.it/wiki/Softfork

[dylkil]

When bitcoin launched there were no non-mining nodes, every node was a mining node. "Node" in the whitepaper refers to what we know today as mining nodes. You are suggesting that the task of relaying blocks falls solely on non-mining nodes, when this isnt true. Mining nodes carry out the same roles as non mining nodes when it comes to relaying/propagation. Every node within the network, whether it be mining or non-mining, pass blocks they receive to their peers.

[jude-]

The task of relaying blocks falls to every node; you are correct there (and I never claimed otherwise). But, if a miner produces a block that the vast majority of nodes reject, then the network effectively splits into two parts -- one part where the block was never "seen" and the other part where it was. If the part that never "sees" the block represents more economic activity -- e.g. the majority of exchanges' nodes, the majority of wallets' nodes, etc. -- then it doesn't matter how much mining PoW gets sunk into that block and its descendants because they will never be processed. Downstream, that means that the miner's coins never materialize on these nodes, which makes mining non-relayed blocks unprofitable. Miners need other nodes to recognize their blocks in order for those other nodes' operators to recognize the existence of their coins.

For example, consider what would happen if a miner produced a block that tried to spend a Segwit output without consideration of the witness. Under the Bitcoin protocol, this is technically allowed -- a Segwit output looks like an anyone-can-spend output. But due to the extra Segwit rules, only pre-Segwit nodes would accept and relay this block. Considering that nearly all exchanges, wallets, custodians, etc. apply the Segwit rules, this would mean that this block would be treated as invalid and its coinbase rendered effectively unspendable. Even if 100% of the Bitcoin miners tried to build on top of this Bitcoin-valid but Segwit-invalid block, all their blocks would be similarly rejected. Only pre-Segwit Bitcoin nodes would accept these blocks, but hardly anyone runs them [1] (note that Segwit support first appeared in version 0.16; there are indeed still some people running pre-Segwit nodes).

[1] https://luke.dashjr.org/programs/bitcoin/files/charts/softwa...

[CyberDildonics]

For some reason you seem to think that miners can't send out their own blocks. Of course they can do anything a simple relay node can do.

Also you are linking to a person who thinks the sun revolves around the earth and that there is nothing wrong with slavery because the bible says so.

[CyberDildonics]

Nodes aren't "responsible" for anything, they can only help if they want. Miners broadcast their blocks to other miners to signal they found a valid block.

Miners can broadcast to anyone they want and nodes can't find or manipulate blocks, so they take the role of passive helpers.