A proposition containing two or more simple
A process of linking propositions by
affirming one proposition on the basis of one or more other propositions.
A structured group of propositions reflecting an
A proposition used in an argument to support the
truth of some other proposition.
The proposition in an argument whose
truth is supported by the other propositions.
Asserts that the conclusion necessarily follows
from the premises.
Asserts that the premises make the conclusion
probable or more likely.
Truth of the premises guarantees the
truth of the conclusion.
The truth of the premises does not
support the truth of the conclusion.
Argument is valid and the premises are true.
Argument that is not valid or the premises are not true
Truth of the premises make the conclusion more
Truth of the premises does not make the conclusion more likely.
An argument that is strong with true
An argument that is weak or has a false premise.
Any error in reasoning.
Errors that arise in the construction of deductive arguments.
These fallacies are all characterized
by the fact that the premises are unconnected to and thus can't support the
Fallacies of Relevance
A fallacy in which one is encouraged to believe a proposition because a large number of people also believe it.
Appeal to the populace
A broad class of fallacies that rely
on stirring up the emotions of the listener, rather than providing reasoned
Appeal to Emotion
A fallacy in which a distracting element is
introduced to obscure an opponent's position.
A fallacy in which one intentionally
misrepresents an opponent's position. Generally takes the form of assuming that
one's opponent has adopted the most extreme position possible.
An argument that relies on attacks on
the character of a person making an argument.
A direct attack on character of the person making the
Abusive Ad Hominem
An attack on the circumstances of the person making an
Circumstantial Ad Hominem
An argument that relies on a threat of force.
Appeal to force
An argument in which the premises support a
different conclusion than the one offered.
-Also called non-sequiturs
Missing the point
In these fallacies the premises do
relate to the conclusion, but they aren't strong enough to support the conclusions drawn. These are all weak arguments.
Fallacies of Defective Induction
When a proposition is held to be true because it has not been proven false; or a
proposition is held to be false because it hasn't been proven true.
Argument from Ignorance
A fallacy in which the conclusion is
based on the authority of an individual who has no legitimate claim to
expertise in the matter under consideration.
Appeal to Inappropriate Authority
Something that is not really a cause is treated as a cause. An error that arises from a
misunderstanding of causal relations.
A fallacy in which one event is assumed
to have been caused by a second event because one event came before the other.
Mistaking a temporal relation for a causal relation. Assuming that because A
happened and then B happened, A caused B.
A fallacy in which change in a particular direction is assumed to lead to further disastrous change in the same direction.
A fallacy in which one moves carelessly from individual cases to a generalization.
Fallacies in which the conclusion depends on a tacit assumption that is in error. The fallacy arises from making unwarranted assumptions in the premises.
Fallacies of Presumption
A fallacy in which a generalization is wrongly applied to a specific case.
Basically a situation where someone ignores an obvious exception to a rule.
It is the opposite of a hasty generalization.
A fallacy in which a question is asked in such a way that presupposes the truth of some proposition buried in the question.
A fallacy in which the conclusion is
stated or assumed in one of the premises.
Begging the Question
Fallacies caused by a shift or confusion of meanings within an argument.
Fallacies of Ambiguity
A fallacy in which a word or phrase is
used with different meanings in different parts of an argument.
We have a word with two or more meanings and one shifts from one meaning to another over the course of an argument.
A fallacy in which the grammar is ambiguous, and that ambiguity is exploited in
the argument or claim.
A fallacy in which a premise is
employed to mean different things based on changes in emphasis given to words
within the premise.
A fallacy in which an inference is mistakenly drawn about a whole based on
attributes of the parts.
A fallacy in which we draw an
inference about the parts based on the whole.