The lawyer’s truth is not Truth, but consistency or a consistent expediency.

A distinction is being drawn between what holds together and what is actually so. An argument can be internally flawless, every step following from the last, and still rest on a premise chosen because it was useful rather than because it was true. Consistency is a test a false thing can pass.

So when something is presented to you very tidily, look at the foundations rather than the reasoning. Ask what the first assumption was and who benefits from its being accepted. Airtight logic on a convenient premise is the most persuasive form of being wrong, and it turns up wherever there is something to gain.