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Common Ground and Burden of Proof

Why It Matters

Every unsupported premise is a potential failure point. The more you can build from shared assumptions, the less you have to prove. Understanding where burden of proof lies reveals which claims need evidence and which can be assumed.

The Key Move

Map your argument into:

  1. Premises the audience already accepts (common ground - no proof needed).
  2. Premises you need to establish (burden on you).
  3. Premises they should prove if they reject (burden on them). Restructure to maximize
  4. and strategically place
  5. .

Classic Application

Legal proceedings explicitly allocate burden of proof. Prosecution must prove guilt; defense need not prove innocence. This shapes argument strategy fundamentally - prosecution builds affirmative case, defense merely needs to create reasonable doubt. Different burdens, different strategies.

Surprising Application

API design and technical proposals. When proposing a new approach, you bear the burden of proof against the status quo. Recognizing this means:

  1. Identify what's already accepted (existing patterns, established principles).
  2. Show how your proposal extends these, rather than rejecting them.
  3. Make opponents bear burden of explaining why familiar principles suddenly don't apply. Shifts the rhetorical weight.

Failure Modes

Arguing for claims that don't need arguing (wasting credibility). Treating burden of proof as symmetrical when it's not (defenders have natural advantage). Trying to prove too much - the more you claim, the heavier your burden. Missing implicit common ground and re-arguing settled points.

Go Deeper

Whately's "Elements of Rhetoric" on presumption and burden of proof. Walton's "Burden of Proof" for modern treatment.