agnosticism– The beleive that it is impossible to determine whether God exists. Compare with atheism. See also The Case for
Agnosticism.
a posteriori– Literally, “after experience”. Any knowledge gained through experience or empirical means is said to be known a
posteriori. Contrast with a priori.
a priori– Literally, “before experience”. Any knowledge which is known to be true without appeal to empirical means is said to
be a priori; alternately, “true in all possible worlds”. Kant’s famous example is “2 + 2 = 4″. It is generally conceeded that only
statements of pure mathematics or logic might be considered a priori. Contrast with a posteriori. See also the Internet
Encylcopedia of Philosophy.
analytic– Term used by Immanuel Kant to describe a specific type of proposition; namely, one in which the subject is
contained within the predicate. A classic example of this is the proposition, “A bachelor is an unmarried male.” Since the
predicate ‘unmarried male’ occurs within the concept of ‘bachelor’ (that is, part of the definition of ‘bachelor’ is ‘unmarried
male’) this proposition is analytic. Almost every philosopher has held that analytic proposition must also be a priori, since they
seem “true by definition”. Contrast with synthetic.
antecedent– In logic, the first part of a conditional statement. For examle, in the conditional statement “If it is raining, then I
will take an umbrella” the phrase “it is raining” is the antecedent. Symbolically, this is represented by the term or terms before
the conditional symbol; for example, in the logical statement ‘X
Y’ the ‘X’ is antecedent. See also consequent.
atheism– The belief that God does not exist, and that this fact can be known (and possibly demonstrated). Compare with
agnostic.
axiom– In an axiomatic system, one of the basic hypotheses assumed to be true and from which other statements might be
derived. Compare deduction.
biconditional– In logic, one of the sentential connectives. Expressed “…if and only if…”. A number of notational variants
exist, but within Philosophy for Everyone the symbol ‘
‘ is used to represent the biconditional. A biconditional statement is
true only when both terms have the same truth-value; for example, the logical sentence ‘A
B’ is true only when both ‘A’
and ‘B’ are true, or when both ‘A’ and ‘B’ are false.
bioethics– Area of applied ethics which deals exclusively with medical practice and research.
bourgeois– In Marxist theory, the class of owners. Contrast with proletariat.
Cartesian Method, the– From Descartes, a system whereby one doubts all empirical data as being possibly false. This leads to
Descartes’ one guaranteed truth, “I think, therefore I am”, which is known as the cogito. The reasoning behind this statement is
that while I may be deceived into thinking false things, I know that I am still thinking: therefore, in some sense I must exist.
Compare with epistemology.
Categorical Imperative, the– In Kant’s ethical theory, the supreme moral principle: “So act always in such a way that you
could will your action to be universal law”.
cogito– From Descartes, the statement “cogito ergo sum“, or “I think, therefore I am”. Compare with Cartesian Method.
compatibilism– The theory that universal causation is not incompatible with free will. Most compatibilists accept causation as
true, but hold that moral agents are still responsible for their actions. Contrast with incompatibilism. Compare with
libertarianism and hard determinism. See also Freedom, Determinism and Responsibility.
conclusion– In logic, the final proposition in a chain of reasoning. In a valid derivation, if the premises are true then the
conclusion will also be true.
conditional– In logic, one of the sentential connectives. Expressed ‘if…then’. A number of notational variants exist, but
within Philosophy for Everyone the symbol ‘ ‘ is used to represent the conditional. A conditional statement is only false in the
case where the antecedent is true and the consequent is false.
conjunction– In logic, one of the primitive connectives. Expressed ‘and’. A number of notational variants exist, but
within Philosophy for Everyone the symbol ‘&’ is used to represent the conjunction. A conjunction is true if and only if both
conjuncts (or parts) are true; that is, ‘X & Y’ is true is both ‘X’ and ‘Y’ are true.
consequent– In logic, the second part of a conditional statement. For examle, in the conditional statement “If it is raining,
then I will take an umbrella” the phrase “I will take an umbrella” is the consequent. Symbolically, this is represented by the
term or terms before the conditional symbol; for example, in the logical statement ‘X
Y’ the ‘Y’ is the consequent. See also
antecedent.
contingent– A proposition is said to be contingent if its truth or falsity depends on its agreeing with some state of affairs; that
is, if it is neither tautological or contradictory. For example, the proposition “It is raining outside” is sometimes true and
sometimes false.
contradiction– A proposition of the logical form ‘A & ~A’. Such a proposition is always false. Compare with the Law of
Contradiction. Contrast with tautology.
contradiction, law of– Also called the ‘Law of Non-Contradiction’. One of the ‘Laws of Thought’, expessed symbolically as
‘~(A & ~A’). This means essentially that nothing can both be and not be; for example, at any given time ‘It is raining’ and ‘It is
not raining’ cannot both be true. In logic, a statement of the form ‘A & ~A’ is considered to be a contradiction; that is, it
cannot possibly be true. Compare with law of excluded middle, law of identity, logic, tautology. See also logic.
deduction (deduce)– The process of deriving one proposition from another proposition or a set of propositions. If the original
propositions, or premises, are true then any conclusions derived from them will also be true. Compare derivation. Contrast
induction.
deontological– Any doctrine, generally in Ethics, which holds particular actions to be more important than the perceived
outcome or goal. Contrast with teleological.
derivation– In logic, the formal means of deducing a conclusion from a given set of premises. A valid derivation is ‘truthpreserving’; that is, if the premises are true, the conclusion will always be true.
disjunction– In logic, one of the primitive connectives. Expressed ‘or’. A number of notational variants exists, but
within Philosophy for Everyone the symbol ‘v’ is used to represent disjunction. A disjunction is true if and only if one of the
disjuncts (or parts) is true; that is, ‘X v Y’ is true only if either ‘X’ is true or ‘Y’ is true. Furthermore, an inclusive
disjunction is true if both ‘X’ and ‘Y’ are true, while an exclusive disjunction is false in that case.
dualism– The view that all reality is divided into two seperate and distinct areas or parts. Typical forms of dualism have
included appearance/reality and mind/matter. Contrast with monism. Plato, Aristotle, Descartes and many others have been
dualists.
empirical– Experiential. Knowledge gained empirically is gained through observation of the world. Compare with a
posteriori. Contrast with a priori and pure.
empiricism– A doctrine in epistemology which holds that the source of all human knowledge is experience. Empiricism was
largely a British movement opposed to rationalism. Major proponents of the theory include Locke, Berkeley, and Hume.
epistemology– Branch of philosophy which attempts to answer the question, “What can I know?”. See also the Philosophy for
Everyone epistemology page.
ethics– Branch of philosophy which attempts to answer the question, “What is good?”. See also the Philosophy for
Everyone ethics page.
excluded middle, law of– One of the ‘Laws of Thought’, expressed symbolically as ‘A v ~A’. This means for any statement,
either the affirmative or the negative must be true. In logic, any sentence which appears in the form of the law of the excluded
middle is considered to be a tautology; that is, true in all possible cases. Compare with the Law of Contradiction and the Law of
Identity. See also logic.
formal logic– See logic.
Godel’s Proof– Also known as Godel’s incompleteness theorems. The proof is in two parts and relates to formal systems, as
was composed as a response to Russell and Whitehead’s Principia Mathematica. The first proof is that it is impossible to prove,
for some given system, a true sentence using the language of the system. The second proof is that it is impossible to prove, for
some given system, a sentence which demonstrates the consistency of the system. These proofs demonstrated the impossibility
of the logicist project. See also Kurt Godel.
hard determinism– Theory that: 1) Universal Causation is incompatible with free will, 2) Universal Causation exists,
therefore 3) No moral agents possess free will, and as such cannot be held responsible for their actions. Compare libertarianism
and compatibilism. See also Freedom, Determinism and Responsiblity.
idealism– The monist theory that everything which exists is mental or of the mental world, that physical or material objects are
illusory. Contrast with materialism.
identity, law of– In logic, one of the ‘Laws of Thought’, expressed as “A is A”, wihch means that every statement is or is
identical with itself, and that every statement implies itself. Compare with the Law of Contradiction and the Law of the
Excluded Middle. See also logic.
incompatibilism– The view that universal causation and free will cannot co-exist, or are incompatible. This is held by both
libertarians and hard determinists; however, it is denied by compatibilists. See also Freedom, Determinism and Responsiblity.
induction (induce)– The most typical method of reaching conclusions, and according to empiricists, the only means. The
opposite of deduction, induction is the means of inferring some general law from observed phenomena. Unlike its counterpart,
however, induction does not guarantee its own findings, and any further observation might invalidate one’s conclusions.
informal logic– Also known as critical thinking or critical reasoning. Informal logic is the attempt to apply logical principles to
‘normal thinking’; that is, without the mechanical and symbolic apparatus of formal logic. Oftentimes informal logic uses
inductive principles in addition to deductive ones. What is lost is accuracy and rigour is made up in ease of use.
laws of thought– Three principles classically held to logically define the state of reality; alternately, the classical axioms of
logic (particularly syllogistic logic). The laws of thought are the Law of Contradiction, the Law of the Excluded Middle, and
the Law of Identity. See also logic.
libertarianism– Theory that: 1) Universal Causation is incompatible with free will, 2) Universal Causation does not exist,
therefore 3) Moral agents possess free will, and are therefore responsible for their actions. Compare with compatibilism. See
also Freedom, Determinism and Responsibility.
logic– Also called symbolic logic and formal logic. Both the apparatus of deductive reasoning and the study of that apparatus.
Modern formal logic is axiomatic and, in the main, originated in Russell and Whitehead’s Principia Mathematica. For a more
detailed treatment of symbolic logic, see the Philosophy for Everyone logic page. Contrast with informal logic.
logicism– The project to prove a logical basis for mathematics. The traditional presentation of logicism can be found in the
work of Frege and that of Russell and Whitehead. Logicism was presented with one of the most complete refutations in the
history of philosophy in the form of Godel’s proofs; nonetheless, the project was enormously important in developing the
structure of modern symbolic logic.
materialism– Also called physicalism, the monist theory that everything that exists is material or physical. Materialists deny
that we have non-physical “minds” or “souls”. Contrast with idealism.
metaphysics– Branch of philosophy which attempts to answer the question, “What is there?”. See also the Philosophy for
Everyone metaphysics page.
monism– The view that all of reality is composed of only one substance. The three most common forms of monism are
Idealism, Materialism, and Neutral Monism. Contrast with dualism. This view was held by Spinoza and Berkeley, among
others.
negation– In logic, expressed ‘not’ or ‘it is not the case that’. Symbolically this is expressed within Philosophy for Everyone as
‘~’. Negation asserts that a given sentence is false or, logically equivalently, that its negation is true. For example, ‘~A’ means
that ‘A’ is false, or that the negation of ‘A’ is true (which is the same thing).
notational variant– In logic, any different system of notation which is not taken to alter the meaning; generally, when one
symbol may be substituted throughout with a different symbol without altering the meaning of the system. An obvious example
is Polish notation.
noumenal– In Kant, the “really” real. What provides raw sense-data. According to Kant, we cannot ever know anything about
the noumenal world, since we are aquainted only with the phenomenal world. This distinction allowed him to disregard as
illegitimate the traditional problems of metaphysics, such as the existence of God and the problem of Free Will.
Occam’s Razor– Principle attributed to William of Ockham, although it was used by earlier philosophers. Occam’s razor is the
principle by which, for any theory, non-essential elements should be removed, and the simplest possible formulation is the most
desirable. This principle is often formulated as “entities should not be multiplied beyond neccesity”.
ontology– Branch of metaphysics dealing with questions of existence: “What exists?”
Polish notation– A notational variant of logic, used by logicians such as Lukasiewicz.
phenomenal– In Kant (and post-Kantian philosophy), that which is perceived through the mind. Kant holds in the Critique of
Pure Reason that all of our knowledge is of the phenomenal world; that is, that our minds imposes certain forms (notably,
Space and Time) on our sensory input so that we might understand it. Contrast with noumenal.
premise– In logic, one of the given statements, axioms or assumptions in a derivation. In a valid derivation, if the premises are
true, the conclusion is guaranteed to be true.
proletariat– In Marxist theory, the working class. Contrast with bourgeois.
pure– Often used to signify a priori speculation or argument; that is, devoid of empirical content (which is considered to taint
the results). The aim of many metaphysicians.
Russell’s paradox– The question of whether ‘the set of all sets that do not contain themselves’ is a member of itself or not. If
so, then it is not a member of itself; if it is not, however, then by definition it is. Russell arrived at this problem in attemtping
to disprove Cantor’s suggestion that there is not greatest cardinal number, and it was originally published, along with his
“Theory of Types”, in the Principles of Mathematics. To some degree, Russell and Whitehead’s Principia Mathematica is an
attempt to resolve this paradox. See also logic, set theory, and logicism.
soft determinism– See compatibilism.
synthetic– Term used by Kant to describe a class of propositions. A synthetic proposition is one that is not analytic; that is,
where the subject is not contained within the predicate. Any proposition concerning a realtion between two different concepts
(where one is not defined in terms of the other) is generally synthetic. Kant held that there can be both a priori and a
posteriori synthetic propositions (a contention that later philosophers, notably Wittgenstein, refuted); while the a
posteriori ones are taken to be the normal contingent statements of everyday life (ie, “Ryan is cold”), the a priori synthetic
statements are the domain of metaphysics. Kant’s Critique of Pure Reason is an attempt to prove the existence of such
propositions.
tautology– In logic, a statement which is true a priori, or in ‘all possible worlds’. Logical tauatologies take the form of ‘A v
~A’. Compare with the Law of the Excluded Middle. Contrast with contradiction.
teleological– Any doctrine, usually in ethics, which places great importance upon the telos, or goal. The expression “the end
justifies the means” is a teleological statement. Contrast with deontological.
telos– Greek word meaning ‘end’ or ‘goal’. See teleological.
theory of sets– See set theory.
universal causation– The state of affairs when every event is totally caused by events prior to it. Also known as determinism.
See also Freedom, Determinism and Responsibility.
utilitarianism– A doctrine in ethics. Utilitarianism is distinguished by its use of the Principle of Greatest Good; that is, the
principle whereby an action is considered ‘good’ if its intended effects ought to produce a greater amount of good than evil in the
greatest number of persons.