a posteriori

[ey po-steer-ee-awr-ahy, -ohr-ahy, -awr-ee, -ohr-ee]

adjective

1. from particular instances to a general principle or law; based upon actual observation or upon experimental data.

   an a posteriori argument that derives the theory from the evidence.

2. not existing in the mind prior to or independent of experience.

a posteriori

/ ɑː, -rɪ, eɪ pɒsˌtɛrɪˈɔːraɪ /

adjective

1. relating to or involving inductive reasoning from particular facts or effects to a general principle

2. derived from or requiring evidence for its validation or support; empirical; open to revision

3. statistics See posterior probability

Word History and Origins

Origin of a posteriori¹

1615–25; < Latin: literally, from the one behind. See a- ⁴, posterior

Word History and Origins

Origin of a posteriori¹

C18: from Latin, literally: from the latter (that is, from effect to cause)

When To Use

What does a posteriori mean?

A posteriori is a term applied to knowledge considered to be true based on experience, observation, or existing data. In this sense, a posteriori describes knowledge that requires evidence.A posteriori comes from Latin and literally translates as “from the latter” or “from the one behind.”It’s often applied to things involving inductive reasoning, which uses specific instances to arrive at a general principle or law (from effect to cause).It can be used as an adjective, as in a posteriori knowledge, or as an adverb, as in We acquire knowledge a posteriori—through experience.A posteriori contrasts with a priori, which literally translates as “from the previous” or “from the one before” and is applied to things considered to be true without being based on previous experience or observation. A priori is applied to things that involve deductive reasoning, which uses general principles to arrive at specific facts or conclusions (from cause to effect).Both a priori and a posteriori are used in the context of reasoning and philosophy, especially epistemology, which is the philosophical study of knowledge. Both can also be used generally, though they’re often used formally.Example: It’s a scientist’s job to gather facts a posteriori by careful observation.