Two distinctions will be explored today: the a priori/a posteriori distinction, and the analytic/synthetic distinction.
A priori: A priori means prior to or independent of experience; it is contrasted with ‘a posteriori’ (empirical, posterior to experience). These two terms are primarily used to mark a distinction between:
(1) Two modes of epistemic justification
(2) Kinds of propositions
(3) Kinds of knowledge
(4) Kinds of argument
(5) Two ways in which a concept or idea may be acquired
Let’s unpack each of these below. Most, but not all, of the content below is quoted from the Cambridge Dictionary of Philosophy. The numbers correspond with the 5 ways of unpacking the distinction mentioned above.
(1) A belief or claim is said to be justified a priori if its epistemic justification, the reason or warrant for thinking it to be true, does not depend at all on sensory or introspective or other sorts of experience; whereas if its justification does depend at least in part on such experience, it is said to be justified a posteriori or empirically. This specific distinction has to do only with the justification of the belief, and not at all with how the constituent concepts are acquired; thus it is no objection to a claim of a priori justificatory status for a particular belief that experience is required for the acquisition of some of the constituent concepts. [Although the aforementioned conception is negative, there have been positive conceptions]. Historically, the main positive conception was that offered by proponents of rationalism (such as Plato, Descartes, Spinoza, and Leibniz), according to which a priori justification derives from the intuitive apprehension of necessary facts pertaining to universals and other abstract entities. In contrast, proponents of traditional empiricism typically attempt to account for such justification by appeal to linguistic or conceptual conventions.
(2) A proposition that is the content of an a priori justified belief is often referred to as an a priori proposition (or an a priori truth).
(3) If, in addition to being justified a priori or a posteriori, a belief is also true and satisfies whatever further conditions may be required for it to constitute knowledge, that knowledge is derivatively characterized as a priori or a posteriori (empirical), respectively. Examples of knowledge that have been classically regarded as a priori in this sense are mathematical knowledge, knowledge of logical truths, and knowledge of necessary entailments and exclusions of commonsense concepts (‘Nothing can be red and green all over at the same time’, ‘If A is later than B and B is later than C, then A is later than C’); but many claims of metaphysics, ethics, and even theology have also been claimed to have this status.
(4) A deductively valid argument that also satisfies the further condition that each of the premises (or sometimes one or more particularly central premises) are justified a priori is referred to as an a priori argument. This label is also sometimes applied to arguments that are claimed to have this status, even if the correctness of this claim is in question.
(5) In addition to the uses just catalogued that derive from the distinction between modes of justification, the terms ‘a priori’ and ‘a posteriori’ are also employed to distinguish two ways in which a concept or idea might be acquired by an individual person. An a posteriori or empirical concept or idea is one that is derived from experience, via a process of abstraction or ostensive definition. In contrast, an a priori concept or idea is one that is not derived from experience in this way and thus presumably does not require any particular experience to be realized.
A posteriori: Justified by experience.
For example: The cat is on the mat.
A synthetic statement/proposition is one in which the predicate is not contained in the subject. The predicate goes beyond the subject. Synthetic statements generally refer to matters of fact rather than relations of concepts/ideas.
Example: This triangle is blue.
An analytic statement/proposition is one in which the predicate is contained in the subject. This refers to relations between concepts/ideas. The statement is true in virtue of the meanings of the terms.
Example: All bachelors are unmarried.
Regarding the analytic/synthetic distinction, the Cambridge Dictionary of Philosophy writes the following:
The distinction, made famous by Kant, according to which an affirmative subject-predicate statement (proposition, judgment) is called analytic if the predicate concept is contained in the subject concept, and synthetic otherwise. The statement ‘All red roses are red’ is analytic, since the concept ‘red’ is contained in the concept ‘red roses’. ‘All roses are red’ is synthetic, since the concept ‘red’ is not contained in the concept ‘roses’. The denial of an affirmative subject-predicate statement entails a contradiction if it is analytic. E.g., ‘Not all red roses are red’ entails ‘Some roses are both red and not red’
Philosophers since Kant have tried to clarify the analytic–synthetic distinction, and generalize it to all statements. On one definition, a sentence is analytic provided it is “true solely in virtue of the meaning or definition of its terms.” The truth of any sentence depends in part on the meanings of its terms.
A more adequate generalization defines an analytic statement as a formal logical truth: one “true in virtue of its logical form,” so that all statements with the same form are true.
In the next and final post in the philosophical terminology series, I will consider objects, properties, and relations. I hope you can join me!