Editing Inductive reasoning (section)

=== Argument from analogy ===
{{Main|Argument from analogy}}

The process of analogical inference involves noting the shared properties of two or more things and from this basis inferring that they also share some further property:<ref name="Baronett">{{Cite book|title=Logic|last=Baronett|first=Stan|publisher=Pearson Prentice Hall|year=2008|location=Upper Saddle River, NJ|pages=321–25}}</ref>

:P and Q are similar with respect to properties a, b, and c.
:Object P has been observed to have further property x.
:Therefore, Q probably has property x also.

Analogical reasoning is very frequent in [[common sense]], [[science]], [[philosophy]], [[law]], and the [[humanities]], but sometimes it is accepted only as an auxiliary method. A refined approach is [[case-based reasoning]].<ref>For more information on inferences by analogy, see [http://www.cs.hut.fi/Opinnot/T-93.850/2005/Papers/juthe2005-analogy.pdf Juthe, 2005] {{Webarchive|url=https://web.archive.org/web/20090306070520/http://www.cs.hut.fi/Opinnot/T-93.850/2005/Papers/juthe2005-analogy.pdf |date=6 March 2009 }}.</ref>

:Mineral A and Mineral B are both igneous rocks often containing veins of quartz and are most commonly found in South America in areas of ancient volcanic activity.
:Mineral A is also a soft stone suitable for carving into jewelry.
:Therefore, mineral B is probably a soft stone suitable for carving into jewelry.

This is ''analogical induction'', according to which things alike in certain ways are more prone to be alike in other ways. This form of induction was explored in detail by philosopher John Stuart Mill in his ''System of Logic'', where he states, "[t]here can be no doubt that every resemblance [not known to be irrelevant] affords some degree of probability, beyond what would otherwise exist, in favor of the conclusion."<ref>A System of Logic. Mill 1843/1930. p. 333</ref> See [[Mill's Methods]].

Some thinkers contend that analogical induction is a subcategory of inductive generalization because it assumes a pre-established uniformity governing events.{{Citation needed|date=June 2020}} Analogical induction requires an auxiliary examination of the ''relevancy'' of the characteristics cited as common to the pair. In the preceding example, if a premise were added stating that both stones were mentioned in the records of early Spanish explorers, this common attribute is extraneous to the stones and does not contribute to their probable affinity.

A pitfall of analogy is that features can be [[cherry-picked]]: while objects may show striking similarities, two things juxtaposed may respectively possess other characteristics not identified in the analogy that are characteristics sharply ''dis''similar. Thus, analogy can mislead if not all relevant comparisons are made.