The white paper is really clear that, to be a node, you have to mine.

The steps to run the network are as follows:

1) New transactions are broadcast to all nodes.
2) Each node collects new transactions into a block.

(nodes create blocks)

3) Each node works on finding a difficult proof-of-work for its block.

(nodes perform proof of work)

4) When a node finds a proof-of-work, it broadcasts the block to all nodes.

(nodes transmit the blocks they've found)

5) Nodes accept the block only if all transactions in it are valid and not already spent.
6) Nodes express their acceptance of the block by working on creating the next block in the chain, using the hash of the accepted block as the previous hash.

(nodes extend blocks)

"Nodes," according to the white paper, are miners. Why is this? Satoshi was clear:

If the majority were based on one-IP-address-one-vote, it could be subverted by anyone able to allocate many IPs.

Nonmining relay nodes are trivial to Sybil attack. In fact, if there was a way to detect whether the node one is connecting to is contributing hashpower or not, we could eliminate nonmining relay nodes altogether and greatly increase the security and upgradeability of the network.
Nonmining relay nodes are our problem. Fix this, fix Bitcoin.
Meanwhile, you've got 1-meg Greg spouting this sort of deliberate disinformation:

There were nodes before miners - Greg Maxwell
How can one read this as anything other than a deliberate attempt to rewrite the white paper, one Reddit post at a time?

https://www.reddit.com/r/btc/comments/6dfkcv/nodesminers_and_only_miners_proof_satoshi_...