From: Les
Vaches
Date: Jan 31, 2007 3:48 AM
Compiled by Jim Walker
originated: 27 July 1997
additions made: 26 March 2004
When arguing with someone in an attempt to get at an answer or an explanation,
you may come across a person who makes logical fallacies. Such discussions
may prove futile. You might try asking for evidence and independent
confirmation or provide other hypothesis that give a better or simpler
explanation. If this fails, try to pinpoint the problem of your arguer's
position. You might spot the problem of logic that prevents further
exploration and attempt to inform your arguer about his fallacy. The
following briefly describes some of the most common fallacies:
ad hominem: Latin for "to the man." An arguer who uses ad hominems attacks
the person instead of the argument. Whenever an arguer cannot defend
his position with evidence, facts or reason, he or she may resort to
attacking an opponent either through: labeling, straw man arguments,
name calling, offensive remarks and anger.
appeal to ignorance (argumentum ex silentio) appealing to ignorance
as evidence for something. (e.g., We have no evidence that God doesn't
exist, therefore, he must exist. Or: Because we have no knowledge of
alien visitors, that means they do not exist). Ignorance about something
says nothing about its existence or non-existence.
argument from omniscience: (e.g., All people believe in something. Everyone
knows that.) An arguer would need omniscience to know about everyone's
beliefs or disbeliefs or about their knowledge. Beware of words like
"all,"
"everyone," "everything," "absolute."
appeal to faith: (e.g., if you have no faith, you cannot learn) if the
arguer relies on faith as the bases of his argument, then you can gain
little from further discussion. Faith, by definition, relies on a belief
that does not rest on logic or evidence. Faith depends on irrational
thought and produces intransigence.
appeal to tradition (similar to the bandwagon fallacy): (e.g., astrology,
religion, slavery) just because people practice a tradition, says nothing
about its viability.
argument from authority (argumentum ad verecundiam): using the words
of an "expert" or authority as the bases of the argument instead of
using the logic or evidence that supports an argument. (e.g., Professor
so-and-so believes in creation-science.) Simply because an authority
makes a claim does not necessarily mean he got it right. If an arguer
presents the testimony from an expert, look to see if it accompanies
reason and sources of evidence behind it.
argument from adverse consequences: (e.g., We should judge the accused
as guilty, otherwise others will commit similar crimes) Just because
a repugnant crime or act occurred, does not necessarily mean that a
defendant committed the crime or that we should judge him guilty. (Or:
disasters occur because God punishes non-believers; therefore, we should
all believe in God) Just because calamities or tragedies occur, says
nothing about the existence of gods or that we should believe in a certain
way.
argumentum ad baculum: An argument based on an appeal to fear or a threat.
(e.g., If you don't believe in God, you'll burn in hell)
argumentum ad ignorantiam: A misleading argument used in reliance on
people's ignorance.
argumentum ad populum: An argument aimed to sway popular support by
appealing to sentimental weakness rather than facts and reasons.
bandwagon fallacy: concluding that an idea has merit simply because
many people believe it or practice it. (e.g., Most people believe in
a god; therefore, it must prove true.) Simply because many people may
believe something says nothing about the fact of that something. For
example many people during the Black plague believed that demons caused
disease. The number of believers say nothing at all about the cause
of disease.
begging the question (or assuming the answer): (e.g., We must encourage
our youth to worship God to instill moral behavior.) But does religion
and worship actually produce moral behavior?
circular reasoning: stating in one's proposition that which one aims
to prove. (e.g. God exists because the Bible says so; the Bible exists
because God influenced it.)
composition fallacy: when the conclusion of an argument depends on an
erroneous characteristic from parts of something to the whole or vice
versa.
(e.g., Humans have consciousness and human bodies and brains consist
of atoms; therefore, atoms have consciousness. Or: a word processor
program consists of many bytes; therefore a byte forms a fraction of
a word
processor.)
confirmation bias (similar to observational selection): This refers
to a form of selective thinking that focuses on evidence that supports
what believers already believe while ignoring evidence that refutes
their beliefs. Confirmation bias plays a stronger role when people base
their beliefs upon faith, tradition and prejudice. For example, if someone
believes in the power of prayer, the believer will notice the few "answered"
prayers while ignoring the majority of unanswered prayers (which would
indicate that prayer has no more value than random chance at worst or
a placebo effect, when applied to health effects, at best).
confusion of correlation and causation: (e.g., More men play chess than
women, therefore, men make better chess players than women. Or: Children
who watch violence on TV tend to act violently when they grow up.) But
does television programming cause violence or do violence oriented children
prefer to watch violent programs? Perhaps an entirely different reason
creates violence not related to television at all. Stephen Jay Gould
called the invalid assumption that correlation implies cause as "probably
among the two or three most serious and common errors of human reasoning"
(The Mismeasure of Man).
excluded middle (or false dichotomy): considering only the extremes.
Many people use Aristotelian either/or logic tending to describe in
terms of up/down, black/white, true/false, love/hate, etc. (e.g., You
either like it or you don't. He either stands guilty or not guilty.)
Many times, a continuum occurs between the extremes that people fail
to see. The universe also contains many "maybes."
half truths (suppressed evidence): An statement usually intended to
deceive that omits some of the facts necessary for an accurate description.
loaded questions: embodies an assumption that, if answered, indicates
an implied agreement. (e.g., Have you stopped beating your wife yet?)
meaningless question: (e.g., "How high is up?" "Is everything possible?")
"Up" describes a direction, not a measurable entity. If everything proved
possible, then the possibility exists for the impossible, a contradiction.
Although everything may not prove possible, there may occur an infinite
number of possibilities as well as an infinite number of impossibilities.
Many meaningless questions include empty words such as "is," "are,"
"were,"
"was," "am," "be," or "been."
misunderstanding the nature of statistics: (e.g., the majority of people
in the United States die in hospitals, therefore, stay out of them.)
"Statistics show that of those who contract the habit of eating, very
few survive." -- Wallace Irwin
non sequitur: Latin for "It does not follow." An inference or conclusion
that does not follow from established premises or evidence. (e.g., there
occured an increase of births during the full moon. Conclusion: full
moons cause birth rates to rise.) But does a full moon actually cause
more births, or did it occur for other reasons, perhaps from expected
statistical variations?
observational selection (similar to confirmation bias): pointing out
favorable circumstances while ignoring the unfavorable. Anyone who goes
to Las Vegas gambling casinos will see people winning at the tables
and slots.
The casino managers make sure to install bells and whistles to announce
the victors, while the losers never get mentioned. This may lead one
to conclude that the chances of winning appear good while in actually
just the reverse holds true.
post hoc, ergo propter hoc: Latin for "It happened after, so it was
caused by." Similar to a non sequitur, but time dependent. (e.g. She
got sick after she visited China, so something in China caused her sickness.)
Perhaps her sickness derived from something entirely independent from
China.
proving non-existence: when an arguer cannot provide the evidence for
his claims, he may challenge his opponent to prove it doesn't exist
(e.g., prove God doesn't exist; prove UFO's haven't visited earth, etc.).
Although one may prove non-existence in special limitations, such as
showing that a box does not contain certain items, one cannot prove
universal or absolute non-existence, or non-existence out of ignorance.
One cannot prove something that does not exist. The proof of existence
must come from those who make the claims.
red herring: when the arguer diverts the attention by changing the subject.
reification fallacy: when people treat an abstract belief or hypothetical
construct as if it represented a concrete event or physical entity.
Examples: IQ tests as an actual measure of intelligence; the concept
of race (even though genetic attributes exist), from the chosen combination
of attributes or the labeling of a group of people, come from abstract
social constructs; Astrology; god(s); Jesus; Santa Claus, etc.
slippery slope: a change in procedure, law, or action, will result in
adverse consequences. (e.g., If we allow doctor assisted suicide, then
eventually the government will control how we die.) It does not necessarily
follow that just because we make changes that a slippery slope will
occur.
special pleading: the assertion of new or special matter to offset the
opposing party's allegations. A presentation of an argument that emphasizes
only a favorable or single aspect of the question at issue. (e.g. How
can God create so much suffering in the world? Answer: You have to understand
that God moves in mysterious ways and we have no privilege to this knowledge.
Or: Horoscopes work, but you have to understand the theory behind
it.)
statistics of small numbers: similar to observational selection (e.g.,
My parents smoked all their lives and they never got cancer. Or: I don't
care what others say about Yugos, my Yugo has never had a problem.)
Simply because someone can point to a few favorable numbers says nothing
about the overall chances.
straw man: creating a false scenario and then attacking it. (e.g., Evolutionists
think that everything came about by random chance.) Most evolutionists
think in terms of natural selection which may involve incidental elements,
but does not depend entirely on random chance. Painting your opponent
with false colors only deflects the purpose of the argument.
two wrongs make a right: trying to justify what we did by accusing someone
else of doing the same. (e.g. how can you judge my actions when you
do exactly the same thing?) The guilt of the accuser has no relevance
to the discussion.
Science attempts to apply some of the following criteria:
1) Skepticism of unsupported claims
2) Combination of an open mind with critical thinking
3) Attempts to repeat experimental results.
4) Requires testability
5) Seeks out falsifying data that would disprove a hypothesis
6) Uses descriptive language
7) Performs controlled experiments
8) Self-correcting
9) Relies on evidence and reason
10) Makes no claim for absolute or certain knowledge
11) Produces useful knowledge
Pseudoscience and religion relies on some of the following criteria:
1) Has a negative attitude to skepticism
2) Does not require critical thinking
3) Does not require experimental repeatability
4) Does not require tests
5) Does not accept falsifying data that would disprove a hypothesis
6) Uses vague language
7) Relies on anecdotal evidence
8) No self-correction
9) Relies on belief and faith
10) Makes absolute claims
11) Produces no useful knowledge
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