Inductive Analogy
A type of Argument by Analogy used to make empirical predictions: inferring that something will behave in a new case the way it behaved in a similar past case.
1. Past cases A1, A2, ..., An share properties P1, ..., Pn with case B.
2. In all past cases, property Q held.
∴ 3. Q (probably) holds in B too.
Example
- This drug worked on mice (similar physiology), so it will probably work on humans
- The last three economic downturns followed inverted yield curves; the curve just inverted again, so we should expect another downturn
- Past medications in this class caused liver effects; the new one likely will too
What makes it strong:
- Base cases are numerous and varied: diversity rules out coincidence
- Shared properties are causally relevant to Q
- The target case isn’t disanalogous in some critical respect (mice ≠ humans defeats some drug analogies)
What makes it weak:
- Sample of one (just one prior case)
- Shared properties are surface-level, not mechanistically connected to Q
- Cherry-picked base cases
Inductive analogy predicts what is; Consistency Analogy argues for what ought to be. Same logical structure, different conclusions and standards.