This does need to elucidated unequivocally. I don't think it is my role to impact Iota's launch. Come-from-Beyond demonstrates a very high S/N ratio, he has brought important ideas to the community which have even aided my design, and who knows I might even want to work with him. Let him get a return on his investment. I have said enough for the time being. I can say more at a future date.
I don't think a general discussion about why you see blocks as essential will be seen as an attack on Iota. I'd also like to know for my own learning process what ambiguities in particular you are referring to with double spends in a generic system with multiple chains of POW.
I want to write that white paper.
I want to write that white paper.
That's good, but it's a shame you can't talk about the ambiguity; I think it's possible you may have overlooked something in your analysis. There again, I may be plainly wrong, but I am happy to be proved wrong.
For us to be sure that all chains would never end up creating a double-spend (i.e. that they watch each other in real-time) would require signing all transactions
synchronously (one after the other, so the entire world has a simultaneity requirement to stand in a global queue to send a transaction), which is of course impractical.
So there will be windows of propagation wherein double-spends can be inserted in various places in the DAG that invalidate good transactions.
The ambiguity is which of the double-spends is the valid one. You proposed a rule that selects the double-spend with the greatest succeeding cumulative proof-of-work, but it is possible this is also ambiguous. Can you really not graph scenarios to confirm this to yourself? I suspect your myopia is because you didn't do a holistic analysis. Incorporate the first paragraph above and then suddenly it becomes clear that the longest chain rule is ambiguous within the propagation window of asynchronous activity. Now do you start to see why it is impossible to resolve ambiguity without a block chain.
Fuserleer pay attention.
In that case can't you drop both of the transactions ? If it's truly impossible to form consensus on which of 2 conflicting tx is supposed to be apended/included then drop them both.
But maybe I'm thinking a little to simple here and am missing the bigger picture.