Washington & Lee University

A Rough Glossary of Some Philosophical Terms

Prof. Gregory

A Rough Glossary of Some Philosophical Terms

Note: There is also a brief glossary in the back of Problems in Mind.

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a posteriori
Posterior to and dependent on sensory or introspective experience. See a priori.
a priori
Logically prior to or independent of experience. Depending on reason alone, self-evident. A belief or claim may be said to be justified or known a priori (or a posteriori). Beliefs or claims which are supposed to be justifiable or knowable a priori are sometimes called a priori claims. Note that the priority claimed is logical or epistemological, not psychological or generative. It is a question of justification, not acquisition of the concepts involved in making or understanding the claim; thus experience may be necessary to understand the claim (one must learn a language), yet be unnecessary for its justification. This last point, and the question of whether there is any such thing as a priori justification/knowledge is debatable.
artificial intelligence

Behaviorism is usefully split into two kinds, with the first further split into two sub-kinds:

Most generally, the view that there are two basic ontological categories. In the philosophy of mind this is a family of positions regarding the ontological problem dividing roughly as follows:

See also monism, materialism, minimal physicalism.

eliminative materialism
A non-reductive materialism. See materialism.

The study of the nature knowledge and justification, and the extent to which we have either.
folk psychology
The common-sense, pre-theoretical, “person in the street” understanding of our mental lives and outward behavior, which also forms the starting point of just about all scientific psychology. Though this is controversial in certain ways, folk psychology can be considered a sort of folk theory containing (on the one hand) propositional attitude or belief-desire psychology—relating beliefs and desires to actions; and (on the other hand) the common introspective vocabulary for qualitative mental states (qualia), such as sensation and emotion.
Though consistent with dualism and idealism, this usually takes the form of a non-reductive materialism. See materialism.
identity theory
Type identity theory is an alternate name for reductive materialism. See also token identity.
intensional fallacy


Most generally, the view that the one basic ontological category is material substance or physical substance (for most of our purposes ‘material’ and ‘physical’ will be used equivalently, though the latter connotes some sort of privileged status for current scientific methodology, whereas the former does not). In the philosophy of mind this is a family of positions regarding the ontological problem dividing roughly as follows:
The study of the fundamental nature of being and reality; supposedly distinct from physics, as it attempts to consider issues concerning the existence and nature of non-physical entities, or the nature of being and reality as such (in itself). See ontology, epistemology.
minimal physicalism
According to Jaegwon Kim minimal physicalism is comprised of three claims:

See also dualism, materialism.

Most generally, the view that there one basic ontological category. In the philosophy of mind this encompasses two positions regarding the ontological problem, idealism, and materialism.
nomological danglers

non-reductive materialism
A subset of materialist positions which, in various ways, deny that mental states are reducible to or identical to physical states. Most non-reductive materialists, while denying type identity of mental states and physical states, assert token identity of mental states and physical states.
Ockham’s razor
Methodological principle which favors simpler theories over more complex theories. The question of what counts as simplicity and in what aspect a theory ought to enjoy it is a difficult one; the number of types of entities the theory posits (don’t posit more types of things than you need) or the number of basic assumptions it involves (simplify the inferential base) are two places one might require simplicity. Named for William of Ockham (c.1285-1347), English Scholastic philosopher, the principle dates back to Aristotle (384-322 BCE).
ontological problem
Also called the mind-body problem, this is the problem of determining the fundamental nature of mental states and processes as well as their relation to physical/material states and processes. See dualism, monism, materialism.
Metaphysics, or a subdiscipline of metaphysics which investigates the fundamental kinds of entities and relations which hold between them. The ontological commitments of a theory—i.e., what kinds of entities a theory assumes to exist; e.g., the ontology of Cartesian dualism is different from that of eliminative materialism.
operational definition
This form of definition defines a term via the intersubjectively observable tests we could carry out in order to determine whether the term applies. A slightly oversimplified example is ‘x is soluble’ is equivalent to ‘if x were put in unsaturated water, x would dissolve. This style of definition is important to, among other things, behaviorism and behaviorist semantics.
ostensive definition


See materialism.
prima facie
at first glance, on the first appearance. In legal contexts prima facie evidence is considered sufficient to establish a claim in the absence of counter-evidence; hence, in this context prima facie evidence is relatively strong. In much philosophical writing, however, it is most often the case that reasons or evidence is called prima facie as a rhetorical preamble to presenting counter-evidence or counter-argument. Thus, in philosophical contexts ‘prima facie’ carries the connotation not of strength, but of weakness.
propositional attitudes
(PAs) Attitudinal states of persons which can be expressed in the form X verbs that P, where X designates a person, verb is an attitudinal verb such as ‘believes’, or ‘desires’, or ‘fears’, and P is a sentence or proposition. This is a large part of folk and scientific psychology, as belief-desire explanations appear to be the way we predict and explain people’s (including our own) behavior. Example: Fred believes that there is a wasp buzzing about him; he wants to avoid getting stung (Fred desires that Fred does not get stung); Fred is afraid that he will have an allergic reaction to the sting of a wasp; Fred runs through the yard shrieking and waving his arms wildly. The last one is not a PA, but a description of behavior which (as lightly illustrated) could be explained/predicted by folk psychological propositional attitude ascriptions.
(QUAIL-yuh or QUAL-yuh singular: quale, QUAL-ee or -ay). Often referred to a “raw feels”, qualia are those subjective, qualitative properties of mental states such as sensations and emotions—the “what it is like” to see red, feel pain, be angry. Such mental states are thought to have intrinsic qualitative features by which we identify them through introspection.
reduction, intertheoretic
One theory and/or domain of theoretical entities is said to reduce to (or be identifiable with) a second theory or domain of entities if, loosely speaking, the second theory captures all that the former does (and more); e.g., Newtonian physics may be said to reduce to the more encompassing Special & General Relativity. But making this idea precise is problematic: classical views of the reduction relation between scientific theories are often too restrictive, requiring full translation of one theory into another, true identity claims regarding entities in the reduced and reducing domain, or that the reduced theory be implied by the reducing theory (with additional assumptions). Churchland analyzes the relation differently: T-old reduces to T-new just in case T-new implies a set of sentences which is smoothly isomorphic with T-old; only then are we warranted in making identity claims or claims of reduction. Note that smoothness is a matter of degree, and that at the opposite end of the continuum from reduction is elimination—T-new takes over, and T-old is rejected as radically false (as opposed to false in the way in which Newtonian physics is false).
reductive materialism
See materialism.
scientific realism


supervene, supervenience
See minimal physicalism.
Turing machine

Turing, A.

token identity theory
A weaker position than type identity/reductive materialism, this position holds that every particular mental state (e.g., the pain in my left ankle the instant after I first sprained it) is identical to some particular physical state, but that mental state types (e.g., pains in general, or even ankle-sprain pains in general) are not identical to physical state types. See non-reductive materialism.
type identity theory
Alternate name for reductive materialism.
In developing this glossary I have, in some cases, relied heavily on the following:
Matter and Consciousness, Paul M. Churchland. MIT Press (1997).
Philosophy of Mind, Jaegwon Kim. Westview (1998).
The Cambridge Dictionary of Philosophy, Robert Audi, ed. Cambridge UP (1995).