Tentmakers
VA Beach
February 2011
Logic
 Ordered thinking
 “Logic is the study of right reasons or valid inferences
and the attending fallacies, formal and informal.”
 I Corinthians 14:33 – God is a god of order!
 John 1 – “Logos” is the order/logic/wisdom/reason of
God
 Genesis 1:1-2 – God makes order out of chaos
 Logic is the basis for exegesis/hermeneutics of the
Scripture.
 Logic is necessary for presenting reasons/defense for
the hope that you have.
 Logic will help you connect with different people and
different worldviews to evangelize more effectively.
 Logic will help you discern between false and sound
doctrines.
It is the glory of God to conceal a
matter; to search out a matter is the
glory of kings.
-Proverbs 25:2
Four Rules of Aristotelian Logic
1. Rule of Identity: A is A
2. Rule of Non-Contradiction: A is not (-A)
3. Rule of Excluded Middle: Either A or (-A)
4. Rule of Rational Inference
Inductive
Deductive
Particular to general
General to particular
Particular to particular
General to general
Effect to cause
Cause to effect
Reasoning after facts
Reasoning before facts
Scientific/legal reasoning
Philosophical reasoning
Probable conclusion
Necessary conclusion
 Argument: a collection of related propositions
resulting in a conclusion
 Proposition: a declarative statement that affirms or
denies something
 Premise: a proposition that sets forth a reason to draw
a conclusion
 Conclusion: a proposition derived from the inferences
of its premises
 Basic argument in deductive logic that takes the
following form:
Premise 1
Premise 2
Conclusion
 Premise 1: Only doers of the whole Law are righteous.
 Premise 2: Jews do not do the whole Law.
 Conclusion: Jews are not righteous.
Romans
2:12-13
Romans
2:17-24
Romans
3:9, 23
 Gathering and synthesizing evidence/reasons that
funnel toward a general conclusion.
Evidence
2
Evidence
1
Evidence
3
Conclusion
Acts 2 – Peter’s Sermon
 Evidence 1: Jesus performed signs and miracles
publicly.
 Evidence 2: God raised Jesus from the dead in
accordance with the Scriptures.
 Evidence 3: Jesus ascended to heaven to be glorified in
accordance with the Scriptures.
 Conclusion: “Therefore, let all Israel be assured of this:
God has made this Jesus, whom you crucified, both
Lord and Christ.”
Acts
2:23-32
Acts
2:22
Acts
2:33-35
Jesus is Lord and Christ!
 Truth: Is the content of the statement accurate in its
meaning?
 Validity: Does the form of the argument reflect proper
steps of reasoning/logic?
 An argument can be valid, without necessarily being
true.
 Have to do with “truth” of the argument/statement.
 Does the content meaningfully and properly relate to
the issue at hand
 Aristotle initially identified 13 logical fallacies; the
number of fallacies varies based on definition
 Has to do with the definition and context of a word or
phrase. By obscuring or changing the definition or context,
one can manipulate an argument or confuse a listener.
 Ambiguity (Amphiboly) - “I really didn’t like the dance.
Young men and women shouldn’t be involved in that.”
 Equivocation (word) – “Giving money to the poor is the
right thing to do. And since the poor have a right to your
money, you should give it before they sue you.”
 Equivocation (context) – “He must really be a spiritual guy.
When he stubbed his toe, I heard him yell ‘goodness,
gracious!’”
 Forms of stereotyping when one uses invalid inductive or
deductive logic to draw conclusions.
 Whole-to-part & Part-to-whole fallacy
 Sweeping generalization (whole-to-part)
 “A” has characteristic X, “P” is a part of A, and therefore has
characteristic X.
 “I went to church and most of the folks I knew were
hypocrites. You go to church, so you must be a hypocrite too.”
 Hasty generalization (Part-to-whole):
 If “A” is X, and “B” is X, then anything with attributes similar
to A and B are also X.
 “I shared my faith with 2 classmates, and they weren’t open. I
guess no one in my class is open!”
 Applying a general rule to a specific case, where the
rule does not apply.
 “Baptism can’t be necessary for salvation. The thief on
the cross was not baptized, but Jesus said they would
be together in Paradise.”
 A non-sequitir fallacy
 If A, then B. Therefore, if B, then A.
 “If you are a true Christian, then you will share your
faith. I know people who share their faith, that means
they must be true Christians.”
 Making a valid set of propositions centering on a
point, only to draw an irrelevant or incorrect
conclusion.
 “God allows the world to continue the way that it is.
God allows people to go on living. God sees all the evil
that is going on. God could end everything, but he
doesn’t. God must not care about the world.”
 Character assassination; attacking the speaker making
the point instead of the point itself
 “There has been much debate about whether Mel
Gibson’s ‘Passion of the Christ’ is historically accurate.
Mel Gibson, alleged to be an alcoholic and antiSemite, is a devout member of a conservative branch of
Catholicism.”
 Manipulating a point by interjecting an emotionally
charged appeal (pity, anger, devotion).
 “How can Christians talk about a ‘good’ God? Read the
OT accounts of warfare and genocide. In the name of
God, the armies of Joshua slaughtered defenseless
women and innocent children! They even slaughtered
the animals! They took no prisoners and killed
defeated soldiers who surely begged and pleaded for
their lives!”
 Tries to persuade someone to accept the truth of a
point because most people believe it.
 “A 1998 poll showed that only 7% of members of the
National Academy of Science believed in a personal
God. Those people would do well to follow the lead of
93% of their colleagues and adjust their beliefs
accordingly.”
 Deciding a point by referencing an authority figure
who agrees with the point
 Note that this fallacy occurs when the authority is
irrelevant to the point at issue or when the issue
resides outside the area of the authority’s expertise.
 “Richard Dawkins is a world famous evolutionary
biologist who holds the Chair of Public Understanding
of Sciences at Oxford University. He does not believe
the Bible is a historically reliable document.”
 When the conclusion is sneaked into the premises;
having already agreed to the premises, the conclusion
is inescapable.
 “Since religion is a collection of unjustified beliefs,
trying to reason with a Christian is pointless. No
matter what happens, their point of view is irrational.”
 Describing an opponents view inaccurately, making it
easier to criticize and reject.
 “Christians who take the Bible literally are ignorant.
How can someone believe that the world was made in
6 days, and believe that Jesus will return with a sword
in his mouth, and understand the basic facts of nature,
biology and evolution?”
 Focusing on evidence that supports a point while
ignoring other relevant evidence that may contradict
it.
 “I went to a church for a little while, and a lot of the
people that I knew were hypocrites. Clearly,
Christianity isn’t something that people can live up to
or really take seriously.”
 Diverting the conversation onto a different track and
arriving at an unrelated point.
 “There has been much debate about the doctrine of
infant baptism. One area of study is the Patristic
writings. Tertullian, an influential early Christian
teacher, argued that baptism was meaningless unless
the believer understood the grace of God. Later in life,
Tertullian was excommunicated from the church for
espousing beliefs about the Holy Spirit that were
deemed heretical. Today, disagreement continues
between believers about the Holy Spirit and miracles.”
 Inaccurately reduces a complex issue into one part of
that issue.
 “Religion is simply humankind’s way of dealing with
anxiety about death.”
 Focuses on the source of a point/issue and argues
against the point/issue by attacking the source.
 “At the Council of Nicaea, the participants discussed
the canon and composition of the Bible. The council
was called together by Constantine – a pagan emperor
concerned with unifying his empire. Considering the
political concerns of Constantine, we should be
skeptical of the contents of the Bible.”
 A fallacy based on confusion
 An “apples-to-oranges” comparison that assumes
something is part of a category to which it does not
really belong.
 “Who made God?”
 Analogies are often used in arguments, and a point can
be manipulated by offering an analogy that does
accurately reflect the issue at hand.
 “There are lots of different kinds of cars, but in the end
they are all vehicles that get you from point A to point
B. In the same way, there are lots of different kinds of
religions, and there’s no reason to prefer Christianity
over any others, except as a matter of opinion or
culture.”
 Also called false dichotomy
 Presents a limited number of options and assumes that
no other options can exist.
 “Faith and reason are irreconcilable. Either you are a
person of faith or you are rational.”
 Also called “post hoc”
 “A” happened before “B”, therefore B happened
because of A.
 “Christianity is a violent religion. Just look at the
Catholic Church in the Middle Ages and you will find
accounts of war, inquisition and execution performed
in the name of Christ.”
For every right way to think, there is a wrong way to
think!
Although Jesus probably existed, reputable Bible
scholars do not in general regard the NT (and
obviously not the OT) as a reliable record of what
actually happened in history, and I shall not consider
the Bible further as evidence for any kind of deity. In
the farsighted word of Thomas Jefferson…’The day will
come when the mystical generation of Jesus…will be
classed with the fable of the generation of Minerva in
the brain of Jupiter.’”
-Richard Dawkins, “The God Delusion”
“The claim that I am an atheist because I don’t understand
‘love’ is particularly ironic. I do understand what love is,
and that is one of the reasons I can never again be a
Christian. Love is not self-denial. Love is not blood and
suffering. Love is not murdering your son to appease your
own vanity. Love is not hatred or wrath, consigning
billions of people to eternal torture because they have
offended your fragile ego or disobeyed your rules. Love is
not obedience, conformity or submission. It is a
counterfeit love that is contingent upon authority,
punishment or reward. True love is respect and
admiration, compassion and kindness, freely given by a
healthy, unafraid human being.”
-Dan Barker, “godless”
Hebrews 11:1 defines faith as ‘the assurance of things hoped
for, the conviction of things not see’. Read in the right way,
this passage seems to render faith entirely self-justifying:
perhaps the very fact that one believes in something which
has not yet come to pass (‘things hoped for’) or for which
one has no evidence (‘things not seen’) constitutes
evidence for its actuality (‘assurance’). Let’s see how this
works: I feel a certain, rather thrilling ‘conviction’ that
Nicole Kidman is in love with me. As we have never met,
my feeling is my only evidence of her infatuation. I reason
thus: my feelings suggest that Nicole and I must have a
special, even metaphysical, connection – otherwise, how
could I have this feeling in the first place? I decide to set
up camp outside her house to make the necessary
introductions; clearly, this sort of faith is tricky business.
-Sam Harris, “End of Faith”