Philosophy for Everyone

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. (more…)

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. (more…)

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. (more…)

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. (more…)