Legal & DebateDUAL-USE

Analogy as Argument

What it is

Reasoning that because two cases are alike in known respects they are alike in the disputed respect — the form of precedent, of the Munich analogy, and of “when I was your age” — whose strength depends entirely on whether the similarities are the ones that matter.

How it works

Douglas Walton's scheme for argument from analogy is simple: case A is similar to case B; A has property P; therefore B has P. The scheme is defeasible, and its critical questions are the whole method: are the cases similar in the respects relevant to P, are there differences that undermine the inference, and is there a better-matching case that points the other way? Dedre Gentner's structure-mapping theory explains why analogies persuade beyond their warrant: people evaluate an analogy by the richness of the relational match, so a vivid, well-structured comparison feels sound even when the mapped relations are not the ones that drive the outcome. Legal reasoning is analogical by design — precedent is the claim that this case is like that one — and distinguishing cases is the disciplined form of the critical questions. Foreign-policy history shows the undisciplined form. Yuen Foong Khong and Ernest May documented how “Munich” was applied to Korea, Vietnam, and later Iraq by decision-makers of both parties, with the analogy selected for its lesson rather than its fit. An analogy is legitimate when the speaker can say which similarities do the work and why the differences do not matter; it is manipulation when it is chosen for its emotional lesson and the disanalogies are left for the audience to fail to notice.

Real-world examples

  • •The Munich analogy: Truman on Korea (1950), Johnson on Vietnam (1965), and the George W. Bush administration on Iraq (2002-2003) each cast negotiation as appeasement; Khong showed that in 1965 the analogy shaped which options were even considered.
  • •Judith Jarvis Thomson's violinist (1971): a thought experiment in which you wake up medically attached to a famous violinist who will die if unplugged — an analogy for pregnancy from rape whose half-century of critics and defenders have argued precisely over which features of the two cases are relevant.
  • •Workplace: “At my last company we did X and it worked” is an analogy whose critical question — is this company like that one in the respects that made X work? — is almost never asked.
  • •Family: “When I was your age I had a job” maps a labor market, a housing market, and a tuition bill that no longer exist onto a child's situation.
  • •Online: “that is exactly like when…” followed by a case that shares one salient feature and none of the structural ones.

Ethical guidelines

Where the line is

Arguing by analogy is legitimate when the speaker identifies the similarities that carry the inference, shows they are the ones relevant to the conclusion, and answers the disanalogies; it becomes manipulation when the comparison is selected for its emotional lesson, the structural differences are left unmentioned, and the felt richness of the match is allowed to stand in for an argument that the cases are alike where it counts.

  • ●State which similarities carry the inference and why the differences do not; an analogy without this is a picture, not an argument.
  • ●Look for the better-matching case before you offer yours, especially if it points the other way.
  • ●Do not choose an analogy for its lesson. Historical analogies chosen for emotional fit are how bad decisions get their confidence.
  • ●When a disanalogy is pointed out, answer it or drop the analogy; do not switch to another analogy with the same lesson.

How to defend against it

  • ►Ask the three critical questions aloud: “Similar in what respects? Are those the respects that matter for this conclusion? What differences would break the inference?”
  • ►Propose the rival analogy: the case that is at least as similar and points the other way. If “this is Munich” is on the table, ask why it is not “this is Vietnam.”
  • ►Distinguish the cases like a lawyer: list the features of the source case that produced the outcome and check each against the target.
  • ►Treat vividness as a warning: the more satisfying the comparison feels, the more likely its structure is doing emotional rather than logical work.

References

  1. Walton, D., Reed, C., & Macagno, F. (2008). Argumentation Schemes. Cambridge University Press
    The scheme for argument from analogy and its critical questions.
  2. Gentner, D. (1983). Structure-Mapping: A Theoretical Framework for Analogy. Cognitive Science, 7(2), 155-170
    Analogies are evaluated by relational structure, which explains their persuasiveness beyond their warrant.
  3. Khong, Y. F. (1992). Analogies at War: Korea, Munich, Dien Bien Phu, and the Vietnam Decisions of 1965. Princeton University Press
    Historical analogies shaping the options considered in the 1965 Vietnam decisions.
  4. May, E. R. (1973). “Lessons” of the Past: The Use and Misuse of History in American Foreign Policy. Oxford University Press
    Decision-makers selecting historical analogies for their lessons rather than their fit.
  5. Thomson, J. J. (1971). A Defense of Abortion. Philosophy & Public Affairs, 1(1), 47-66
    The violinist analogy and the subsequent debate over which similarities are relevant.
Last reviewed
Suggest a correction

Detect Analogy as Argument in any text

Paste any message, email, or article into our free Manipulation Detector to see if Analogy as Argument or other techniques are being used on you.

Try the Detector FreeCreate Free Account