Logic & Apologetics
Why Logic Matters in Christianity
II. The Basic Kind of Arguments
I.
Abductive
II. Inductive
III. Deductive
I.
III. Informal Logical Fallacies Game!
Logic
 Ordered thinking
 “Logic is the study of right reasons or valid inferences
and the attending fallacies, formal and informal.”
 Genesis 1 – God makes order out of chaos
 John 1 – “Logos” is the order/logic/wisdom/reason of
God
Yet Saul grew more and more powerful and baffled the Jews living in
Damascus by proving that Jesus is the Messiah. – Acts 9:22
As was his custom, Paul went into the synagogue, and on three
Sabbath days he reasoned with them from the Scriptures – Acts 17:2
So he reasoned in the synagogue with both Jews and God-fearing
Greeks, as well as in the marketplace day by day with those who
happened to be there. – Acts 17:17
Every Sabbath he reasoned in the synagogue, trying to persuade Jews
and Greeks. – Acts 18:4
For he vigorously refuted his Jewish opponents in public debate,
proving from the Scriptures that Jesus was the Messiah. – Acts 18:28
“But I have had God’s help to this very day, and so I
stand here and testify to small and great alike. I am saying
nothing beyond what the prophets and Moses said would
happen—that the Christ would suffer and, as the first to rise
from the dead, would proclaim light to his own people and to
the Gentiles.”
At this point Festus interrupted Paul’s defense. “You
are out of your mind, Paul!” he shouted. “Your great learning
is driving you insane.”
“I am not insane, most excellent Festus,” Paul replied.
“What I am saying is true and reasonable.”
- Acts 26:22-25
“Apologetics” – The presentation of rational (reasonable)
bases for the validity and defense of Christian beliefs.
“Always be prepared to give an answer to everyone who
asks you to give the reason for the hope that you have.
But do this with gentleness and respect” – I Peter 3:15
Understanding logic and reasoning makes us more
effective in our interactions, dialogues and presentation
of the Christian faith.
No more canned answers!
The building blocks of logical thought and reasoning:
 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
Definition: Inference to the best explanation
Example: “The fist-fight”
In theology and apologetics: Coming to faith based
on experiences and observations
In life we encounter the following:
 Origins of universe
 Origins of life
 Mind, consciousness, personality
 Morality, ethics, conscience, justice
 Love and relationship
 Beauty and aesthetics
 Scripture testimony
 Anthropology of religious belief
 Miraculous/supernatural phenomenon
 Natural law and science
 Logic and reasoning
 Religious conversion and transformation
As separate self-contained observations, these things are peculiar and/or difficult
to explain. But if God actually exists, then it follows as a matter of course that
these things make sense together.
Definition: arriving at a certain conclusion based on the
stated premises
Example: mathematics
In theology and apologetics: “God-friendly” arguments
 The Cosmological Argument
 The Moral Argument
Everything that begins has a cause.
2. The universe has a beginning
3. Therefore, the universe has a cause.
1.
Analyze what properties the “cause” must have and
assess its theological significance.
“God” provides the most reasonable explanation as this
“cause”.
Premise 1 – “Everything that begins has a cause.”
 Has merit both philosophically and experientially
 Past events cannot regress infinitely
 Cause-effect dynamic is experienced generally in life
Premise 2 – “The universe has a beginning.”
 Prevailing scientific theory for the origin of the universe
is “Big Bang Theory”
 13.7 bill years ago the universe exploded into existence
generating all matter and energy
 Expansion of universe and presence of background
radiation
“Therefore the universe has a cause.”
 “Cause” must be:
 Timeless, constant and immaterial
 Agent acting freely without constraint
 An idea-generator with personal dimension - like a
“mind”
 God’s characteristics best fit description of the “cause”
If God does not exist, then objective moral values
and duties do not exist.
2. Objective morals and duties do exist.
3. Therefore, God exists.
1.
Premise 1 – “If God does not exist, then objective morals
and duties do not exist.”
 Without God, moral values are illusory, relative and
come from some naturalistic source (such as evolution).
 A duty to act in a moral way requires accountability, and
naturalistic explanations for morality do not carry a
sense of ultimate “duty” because there is no ultimate
accountability.
 EG. – You could recognize the “good” or “bad” way to act, but
there is nothing compelling a choice to act “good”.
Premise 2 – “Objective morals and duties do exist”.
 Universal presence of “good/bad” values and
“right/wrong” behaviors infer an objective source of
morality
 EG - Is it always wrong to torture and kill a baby for one’s own
pleasure?
 Popular alternative position is “social conditioning”, but
this does not undermine the truth of whether objective
morals and duties actually exist, it only speaks to how we
may discover or understand them. (Like in physical
world).
 Self-defeating logic of relativism
Therefore, God exists.
 Ironically, people generally believe both premises,
though many may attempt to fight the necessary
conclusion!
Definition: compiling evidence that implies a probable
conclusion
Example: lawyer making a case
In theology and apologetics: Peter’s Sermon in Acts 2,
Making the case for the Christ
 Gathering and synthesizing evidence/reasons that
funnel toward a probable conclusion.
Evidence
2
Evidence
1
Evidence
3
Conclusion
Example of Peter’s Sermon in Acts 2
 Evidence 1: Jesus performed signs and miracles
publicly. (Acts 2:22)
 Evidence 2: God raised Jesus from the dead in
accordance with the Scriptures. (Acts 2:24)
 Evidence 3: Jesus ascended to heaven to be glorified in
accordance with the Scriptures. (Acts 2:34)
 Conclusion: “Therefore, let all Israel be assured of this:
God has made this Jesus, whom you crucified, both
Lord and Christ.” (Acts 2:36)
Acts
2:23-32
Acts
2:22
Acts
2:33-35
Jesus is Lord and Christ!
 Have to do with “truthfulness” of the
argument/statement.
 Does the content meaningfully and properly relate to
the issue at hand?
 The 2 most common ways to commit an informal
fallacy is by confusion or irrelevance.
 Confusion – the flow of thinking is mixed-up and out-
of-order
 Irrelevance – the flow of thinking leads to a point
outside of the issue being discussed
“You are a person of faith; I, on the other hand, am a
person of science and reason.”
“I read that most of the members of the National
Academy of Sciences are atheists, so I don’t take religion
very seriously.”
“If you study church history, you see a long tradition of
violence towards dissenters, suppression of scientific
truth, political corruption, wars and bloodshed. Clearly,
the church is anything but a moral influence for good.”
“Centuries before Christ, the Egyptian god Osiris was
said to have died and then risen from the dead. The
Jesus account is another mythical manifestation of this
same earlier story.
“Saying ‘God created the universe’ is not a truly
satisfying explanation of origins, because then you have
to ask the question – ‘Who created God?’”
“I can’t believe that God would allow people to suffer,
burn, and experience pain in a place like hell. If you’ve
ever experienced a moment of torture you know how
horrible it is; then how could you could ever sustain
torture in a place with no hope! The suffering we see in
the world – starvation of children, genocide, war - is
nothing compared to the idea of ‘hell’. How could God
do such a thing?”
“The Bible is just a bunch of fantasy stories featuring
characters like a talking snake, zombies rising from the
dead and magic taking place. We’d never take such
account seriously in a modern setting, and would likely
think the authors had been doing drugs when they
wrote these things.”
“The Bible cannot seriously be considered a relevant
document as it came from a culture where slavery was
legal, women lacked rights and simple modern
conventions like electricity would have been considered
miraculous.”
“I don’t think the Ressurection accounts of the NT are
serious historical events. Christian scholars and
historians who argue that the Resurrection was an
historical event from God do so to justify their livelihood
and get naive people to buy their books.”
“When I read about the pastor of a mega-church who
was recently indicted on charges of fraud and
embezzlement, it reminded me that churches are
money-making operations.”
“Since faith is unjustified and irrational belief.
Arguments that claim to present reasonable bases to
believe in God fall short, because God is a faith-claim
which cannot be justified rationally.”
“Religion has been used to justify horrible things.”
Speaker 1: The gospel of Mark, which is accepted by
scholars as the earliest of the gospels written in the
generation of eyewitnesses, provides an early source for
an eyewitness account of Jesus’ empty tomb, and adds
credibility to the historical claims of the Resurrection.
Speaker 2: Details of the resurrection account described
in Mark differ from some of the details in the other later
gospels. Do you accept Luke, Matthew and John as
credible accounts as well? How do you reconcile the
differences between the accounts?
“As a scientist, I determine what is true based on proof.
Therefore, I cannot accept that God exists unless I can
see the proof of such a claim.”