An alphabetical list of terms or words found in or relating to this blog.


A contrast originally introduced by *Kant between types of proposition. An analytic proposition is one where the concept of the predicate is ‘contained in’ the concept of the subject. ‘All brothers are male’ is an example. A synthetic proposition is one where this is not so, and which is therefore apt for providing substantial information. Kant’s definition is only preliminary, in that not all propositions are of subject-predicate form, and the notion of ‘containment’ is left metaphorical. But his goal of defining a class of propositions that are importantly trivial can be pursued in ways drawing on modern logic. Thus we might define a proposition to be analytic if it has the form of a *tautology, or valid formula of elementary logic, or can be represented as having that form by substitution of synonyms for synonyms. For example, if we substitute ‘male and sibling’ for ‘brother’, then ‘all brothers are male’ is of the form ‘all things that are F and G are F’, and this is a valid formula of the *predicate calculus. The point of Kant’s division is that we might not be too disturbed, philosophically, if everything that can be known *a priori is analytic: analytic truths are so trivial as barely to count as knowledge at all. But if we can know synthetic propositions a priori the question of how such knowledge is possible becomes urgent. Part of the programme of *logical positivism was to show that all a priori propositions are, at bottom, analytic. The entire distinction was queried in one of the most famous papers of modern philosophy, *Quine’s ‘Two Dogmas of Empiricism’ (1950), which attacks the idea that we have a reasonable criterion for synonymy, on which the definition depends.

([1], p. 15)

a priori/a posteriori

A contrast first between propositions. A proposition is knowable a priori if it can be known without experience of the specific course of events in the actual world. It may, however, be allowed that some experience is required to acquire the concepts involved in an a priori proposition. Something is knowable only a posteriori if it cannot be known a priori. The distinction gives one of the fundamental problem areas of *epistemology. The category of a priori propositions is highly controversial, since it is not clear how pure thought, unaided by experience, can give rise to any knowledge at all, and it has always been a concern of *empiricism to deny that it can. The two great areas in which it seems to do so are logic and mathematics, so empiricists have commonly tried to show either that these are not areas of real, substantive knowledge, or that in spite of appearances the knowledge that we have in these areas is actually dependent on experience. The former line tries to show that all a priori propositions are in some sense trivial, or *analytic, or matters of notation or conventions of language. The latter approach is particularly associated with *Quine, who denies any significant split between propositions traditionally thought of as a priori, and other deeply entrenched beliefs that occur in our overall view of the world. Another contested category is that of a priori concepts, supposed to be concepts that cannot be ‘derived’ from experience, but which are presupposed in any mode of thought about the world: time, substance, causation, number, and the self are candidates. The need for such concepts, and the nature of the substantive a priori knowledge to which they give rise, is the central concern of *Kant’s Critique of Pure Reason.

([1], p. 21)


The permanent strand in philosophy that attempts to tie knowledge to experience. Experience is thought of either as the sensory contents of consciousness, or as whatever is expressed in some designated class of statements that can be observed to be true by the use of the senses. Empiricism denies that there is any knowledge outside this class, or at least outside whatever is given by legitimate theorizing on the basis of this class. It may take the form of denying that there is any *a priori knowledge, or knowledge of necessary truths, or any innate or intuitive knowledge or general principles gaining credibility simply through the use of reason; it is thus principally contrasted with *rationalism. An empiricist account of our concepts will hold that they depend upon experience: ‘*nihil in intellectu nisi prius in sensu‘ (nothing in the intellect that was not previously in the senses). Some philosophers such as *Aquinas have held this principle without denying that reason can apprehend knowledge, provided it uses the materials afforded by the sense. One of the main problems for empiricism is to accommodate the way in which thought does not just derive from experience, but provides us with *categories with which to organize it. The necessity for such addition (and its legitimacy) is the central theme of the Critique of Pure Reason of *Kant. Radical empiricism, as espoused by *James, holds that the relations between experiences that are implied in their organization are themselves objects of observation. The key problems for empiricism include avoiding a picture according to which I know nothing but my experiences of the present moment (*scepticism), demarcating the legitimate basis of theory in observation, defending the view that observation is itself free of non-empirical elements, describing legitimate ways of using observation in building a picture of the world, and explaining or explaining away knowledge that appears to have no basis in experience, notably mathematical, logical, or other a priori knowledge.

([1], p. 119)


(Gk., epistēmē, knowledge) The theory of knowledge. Its central questions include the origin of knowledge; the place of experience in generating knowledge, and the place of reason in doing so; the relationship between knowledge and certainty, and between knowledge and the impossibility of error; the possibility of universal *scepticism; and the changing forms of knowledge that arise from new conceptualizations of the world. All of these issues link with other central concerns of philosophy, such as the nature of truth and the nature of experience and meaning. It is possible to see epistemology as dominated by two rival metaphors. One is that of a building or pyramid, built on foundations. In this conception it is the job of the philosopher to describe especially secure foundations, and to identify secure modes of construction, so that the resulting edifice can be shown to be sound. This metaphor favours some idea of the ‘given’ as a basis of knowledge, and of a rationally defensible theory of confirmation and inference as a method of construction. The other metaphor is that of a boat or fuselage, that has no foundations but owes its strength to the stability given by its interlocking parts. This rejects the idea of a basis in the ‘given’, favours ideas of coherence and *holism, but finds it harder to ward off *scepticism. The problem of defining knowledge in terms of true belief plus some favoured relation between believer and the facts began with *Plato’s view in the Theaetetus that knowledge is true belief plus a logos.

([1], p. 123)


A process, such as trial and error, for solving a problem for which no *algorithm exists. A heuristic for a problem is a rule or method for approaching a solution.

([1], p. 173)


Immediate awareness, either of the truth of some proposition, or of an object of apprehension such as a concept. Awareness of the passage of time, or of the ineffable nature of God, have equally been claimed as intuitions. The notion is frequently regarded with suspicion, as simply labelling the place where the philosophical understanding of the source of our knowledge stops. In the philosophy of *Kant intuition (Anschauung) has an empirical form, covering the sensible apprehension of things, and as pure intuition it is that which structures sensation into the experience of things in space and time.

([1], p. 197)


A term especially associated with *Kant, denoting things as they are in themselves, as opposed to things as they are for us, knowable by the senses (*phenomena). The noumenal lies behind the mind-imposed forms of time, space, and causation, and is therefore unknowable. On one view Kant is locked into a ‘two-worlds’ view, so that the noumenal is rather like *Berkeley’s God, in being responsible for the phenomenal world, except that we cannot know anything of its nature. On a different view, the distinction merely reflects Kant’s understanding that all knowledge is knowledge from a standpoint, so the noumenal is the fraudulent idea of that which would be apprehended by a being with no point of view. It is unclear how on Kant’s own view we can mean anything by the term, but Kant does suppose that we need to postulate a noumenal reality and especially a noumenal self as a condition of human *free will, the phenomenal self being all too determined in its actions.

([1], p. 265)


The philosophy of *Comte, holding that the highest or only form of knowledge is the description of sensory phenomena. Comte held that there were three stages of human belief: the theological, the metaphysical, and finally the positive, so-called because it confined itself to what is positively given, avoiding all speculation. Comte’s position is a version of traditional *empiricism, without the tendencies to *idealism or *scepticism that the position attracts. In his own writings the belief is associated with optimism about the scope of science and the benefits of a truly scientific sociology. In the 19th century, positivism also became associated with evolutionary theory, and any resolutely *naturalistic treatment of human affairs. Its descendants include the philosophy of *Mach, and *logical positivism.

([1], p. 294)

The denial of the very possibility of a transcendental reflection on the conditions and meaning of knowledge, and the elevation of the procedures of empirical-analytic science itself to a guarantor of meaningful knowledge.

([2], p. 110)


Any philosophy magnifying the role played by unaided reason, in the acquisition and justification of knowledge. The preference for reason over sense experience as a source of knowledge began the *Eleatics, and played a central role in *Platonism. Its most significant modern development was in the 17th-century belief that the paradigm of knowledge was the non-sensory intellectual intuition that God would have into the workings of all things, and that human beings taste in their acquaintance with mathematics. The Continental rationalists, notably *Descartes, *Leibniz, and *Spinoza, are frequently contrasted with the British empiricists (*Locke, *Berkeley, and *Hume), but such oppositions usually oversimplify a more complex picture. For example, it is worth noticing the extent to which Descartes approves of empirical enquiry, and the extent to which Locke shares the rationalist vision of real knowledge as a kind of intellectual intuition. In spite of the authority of *Kant, the subsequent history of philosophy has tended to minimize or even to deny the possibility of *a priori knowledge, so rationalism depending on this category has also declined. However the idea that the mind comes with pre-formed categories that determine the structure of our language and ways of thought has survived in the work of linguists influenced by *Chomsky. The term rationalism is also used more broadly for any anti-clerical, anti-authoritarian *humanism, but it is unfortunate that it is empiricists such as Hume who are in this other sense rationalists.

([1], p. 318)


One of the three branches into which *semiotics is usually divided: the study of meaning of words, and the relation of signs to the objects to which the signs are applicable. In formal studies, a semantics is provided for a *formal language when an *interpretation or *model is specified. However, a natural language comes ready interpreted, and the semantic problem is not that of specification but of understanding the relationship between terms of various categories (names, descriptions, predicates, adverbs …) and their meanings. An influential proposal is that this relationship is best understood by attempting to provide a *truth definition for the language, which will involve giving a full description of the systematic effect terms and structure of different kinds have on the *truth-conditions of sentences containing them.

([1], p. 346)


The general study of symbolic systems, including language. The subject is traditionally divided into three areas: *syntax, or the abstract study of the signs and their interrelations; *semantics, or the study of the relation between the signs and those objects to which they apply; and *pragmatics, or the relationship between users and the system (C. W. Morris, Foundations of the Theory of Signs, 1938). The tradition of semiotics that follows *Saussure is sometimes referred to as semiology. Confusingly, in the work of *Kristeva, the term is appropriated for the non-rational effluxes of the infantile part of the self.

([1], p. 346)


  • [1]: Blackburn, S. (1996). The Oxford Dictionary of Philosophy (2nd ed.). Oxford, New York: Oxford University Press.
  • [2]: Ulrich, W. (1983). Critical Heuristics of Social Planning: A new approach to practical philosophy. J. Wiley & Sons.