Part 2 · 2 chapters · ~12 min

Arguments: Claims, Evidence and Warrants

The structure of an argument (claim, evidence, warrant, qualifier, rebuttal), common fallacies in technical debates, steelmanning the other side, separating facts from interpretations, and changing your mind in public.

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Structure

Technical arguments go in circles when people argue claims without evidence, or evidence without saying why it supports the claim.

THE SHAPE OF AN ARGUMENT
claim, evidence, warrant, qualifier and rebuttal (after Toulmin)
claim"we should add a read replica"qualifier"for the reporting endpoints"evidence"reports are 40% of DB time"warrant"moving reads off the primary frees capacity"rebuttal"unless reports need fresh data"
swipe the figure sideways, or tap expand for full screen
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claim
The conclusion you want others to accept. State it plainly first.
what you want acceptedstate it first
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Fallacies and steelmanning

fallacyin a design review
appeal to authority"Google does it this way" (Google's constraints are not yours)
false dilemma"either microservices or a big ball of mud" (a modular monolith exists)
straw manarguing against a weaker version of the proposal than the one made
sunk cost"we have spent six months on it, we must finish"
moving the goalpostsnew objections appear each time the previous one is answered
anecdote as data"a customer complained once" against a funnel of thousands

Steelman before you disagree: restate the other position in its strongest form until its author says "yes, that is what I mean". Then respond to that version. It is the fastest way to find out whether you actually disagree.