Philosophical Quotes and Glossary of Terms
Philosophical Quotes
We must follow the argument wherever it leads (Socrates)
Love is desire for the perpetual possession of the good (Plato)
Life is long if you know how to live it (Seneca)
The truth is the whole (G.W.F. Hegel)
He who has a why to live for can bear almost any how (Friedrich Nietzsche)
The limits of my language are the limits of my reality (Ludwig Wittgenstein)
A theory that explains everything, explains nothing (Karl R. Popper)
It is better for rulers to be feared than loved (Niccolo Machiavelli)
Human societies are indeed the result of human action, but not the execution of any human design (Adam Ferguson)
The only freedom which deserves the name is that of pursuing our own good in our own way (John Stuart Mill)
Only that which has no history is definable (Friedrich Nietzsche)
Those who can make you believe absurdities can make you commit atrocities (Voltaire)
It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their own interest (Adam Smith)
The history of all hitherto existing society is the history of class struggles (Karl Marx)
Where there is no law, there is no freedom (John Locke)
It is always better to suffer evil than to do evil (Socrates)
Glossary of Philosophical Terms
Argument or Reasoning: An argument (or reasoning) is a connected series of sentences, statements, or propositions (called “premises”) that are intended to give reasons of some kind for a sentence, statement, or proposition (called “conclusion”).
Validity: An argument is valid if and only if it is not possible that all of its premises are true and its conclusion false. In other words, to say that an argument is “valid” means that the premises are related to the conclusion in such a way that the conclusion must be true if the premises are true, and false otherwise.
Soundness: An argument is sound if and only if a) it is a valid argument and b) its premises are all true.
Negation (“not p”): The negation of a proposition is true just in the cases in which the proposition is false, and it is false just in the cases in which the proposition is true.
Conjunction (“p and q”): The conjunction of two propositions is true only when both propositions are true, and false otherwise.
Disjunction (“p or q”): The disjunction of two propositions is false only when both propositions are false, and true otherwise.
Conditional (“if p, then q”): A conditional is false if the antecedent is true and the consequent is false, and true otherwise.
Biconditional (“p if and only if q”): A biconditional is true if its component propositions have both the same truth value (they are both true or both false), and false if they have different truth values (one is true and the other one is false).
Tautology: A tautology is a formula that is always true regardless of the truth value of its component propositions.
Contradiction: A contradiction is a formula that is always false regardless of the truth value of its component propositions.
Indeterminacy: An indeterminacy is a formula that is true or false depending on the truth value of its component propositions.
Fallacy: A fallacy is an invalid argument that appears to be valid.