Yeah, but P(Valid Critique | Source) is low. For instance, behold as I use it illegitimately against you: "Would you mind linking to where you've seen this use of 'Source?'?"
Besides, legibility is about the argument - it doesn't make sense to talk about a "Source". The source is me. I am the one making the argument.
Statements of fact aren't arguments. "There is a giant octopus besieging NYC right now". There's no argument there. It is merely a statement.
An example legible argument is:
- There is likely a lot of squid ink covering NYC
- This is likely because there is a positively colossal squid creature floating above NYC at the moment
- Squid creatures (colossal or otherwise) discharge ink when attacked
- We are attacking this humongous monstrosity
In fact, "Source?" works better against a legible argument since you can identify which part needs the extra stuff. This argument is fairly legible and is practically just syllogisms. It's merely the case that a premise is wrong - something which you can conclude by asking for the source for a crucial premise.
With an illegible argument, you could debunk the source of one of the claims and still be unable to trace its impact on the conclusion.
For instance:
It's probably raining in NYC right now because it's kind of the conditions that would cause rain if you know what I mean. But there's also this squid creature in the air. It rains when there's squids. Here, read this article about colossal squid ink rain. We all know that squid rain is a thing.
