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APOLOGETICS, LOGIC, AND REASONING
Presented by Ratio Christi TAMU
Logically Captain…
Greek (άπολογία)
APOLOGETICS
WHY APOLOGETICS?
God commands the use of Reason. “but sanctify Christ as Lord in your hearts,
always being ready to make a defense to everyone who asks you to give an account for the hope that is in you, yet with gentleness and reverence.“ (1 Peter 3:15)
Philippians 1:7 Paul speaks of his mission as one of "defending and confirming the gospel.“(Phil 1:16)
IS APOLOGETICS ARGUING?
But avoid foolish controversies, genealogies, quarrels, and fights about the law, because they are useless and empty. (Titus 3:9)
Only if it is foolish!
OBJECTIONS TO APOLOGETICS
There have been many objections to apologetics from Christians:
THE BIBLE DOES NOT NEED TO BE DEFENDED?
"The Word of God is alive and powerful..." (Hebrews 4:12)
The Bible is like a lion; it does not need to be defended but simply let loose. A lion can defend itself. Several things should be noted in response.
THE BIBLE DOES NEED TO BE DEFENDED?
How do we know the Bible is the Word of God?
The Qur'an is alive and powerful and sharper than a two-edged sword....
A roar of a lion speaks with authority only because we know from previous knowledge what a lion can do. Without the tales of woe about a lion's ferocity, its roar would not have the same authoritative effect on us.
JESUS REFUSED TO DO SIGNS FOR EVIL MEN
Jesus rebuked people who sought signs. Hence, we should be content simply to believe without evidence
"A wicked and adulterous generation asks for a miraculous sign!" (Matt. 12:39 cf. Luke 16:31)
JESUS REFUSED TO DO SIGNS FOR EVIL MEN
First, even in this very passage Jesus went on to offer the miracle of His resurrection as a sign of who He was, saying:
"But none will be given it except the sign of the prophet Jonah (Matt. 12:39-40)
PAUL WAS UNSUCCESSFUL IN HIS USE OF REASON ON MARS HILL
Paul was unsuccessful in his attempt to reach the thinkers on Mars Hill (Acts 17)
later telling the Corinthians that he wanted to "know Jesus and Him only" (1 Cor. 2:2)
PAUL WAS UNSUCCESSFUL IN HIS USE OF REASON ON MARS HILL
Paul did have results on Mars Hill Some were saved, including a philosopher A few men became followers of Paul and
believed. Among them was Dionysius, a member of the Areopagus, also a woman named Damaris, and a number of others" (Acts 17:34).
nowhere in either Acts or 1 Corinthians does Paul indicate any repentance or even regret over what he did on Mars Hill
ONLY FAITH, NOT REASON, CAN PLEASE GOD
“Without faith it is impossible to please God.” Heb. 11:16
Asking for reasons, rather than simply believing, would displease God.
ONLY FAITH, NOT REASON, CAN PLEASE GOD
The text does not say that with reason it is impossible to please God.
God in fact calls upon us to use our reason (1 Pet. 3:15) and has given "clear" (Rom. 1:20) and "convincing proofs" (Acts 1:3 NASB) so that we do not have to exercise blind faith.
This text in Hebrews does not exclude "evidence" but actually implies it.
GOD CAN'T BE KNOWN BY HUMAN REASON
“The world by wisdom knew not God" (1 Cor. 1:21 NKJV)
People cannot know the wisdom of God through reason.
GOD CAN'T BE KNOWN BY HUMAN REASON
Paul declared in Romans that the evidence for God's existence is so "plain" as to render even the heathen "without excuse" (Rom. 1:19-20).
The "wisdom" of which he speaks is "the wisdom of this world" (v. 20), not the wisdom of God. Paul called a sophist the "disputer of this age" (v. 20). Sophist could argue for argument's sake. This leads no one to God.
ONLY THE HOLY SPIRIT CAN BRING SALVATION
Salvation is a work of the Holy Spirit. He alone can convict, convince, and convert (John 16:8; Eph. 2:1; Titus 3:5-7).
ONLY THE HOLY SPIRIT CAN BRING SALVATION
The Bible does not teach that the Holy Spirit will always do this apart from reason and evidence.
It is not either the Holy Spirit or Reason.
God is always the efficient cause of salvation, but apologetic arguments can be an instrumental cause used by the Holy Spirit to bring one to Christ.
Greek (λογική)
LOGIC
WHAT IS LOGIC
The science of analyzing
arguments? The science of good reasoning in
general?
Tagore A mind all logic is like a knife all blade, it
makes the hand bleed that uses it
WHAT IS A FORMAL ARGUMENT
Premises that lead to a conclusion P1: If God exists he works all events for the good
of those who believe; P2: Some events produce no good; C: Therefore God does not exist.
The conclusion either follows from the premises logically, or is at least probable given the premises.
√
APOLOGETICS IS NOT USED IN THE BIBLE?
Mostly, the Bible was not written for unbelievers but for believers.
Apologetics IS used in the Bible. Genesis 1 deals with mythical accounts of creation Jesus was constantly proving by signs and wonders
that He was the Son of God (John 3:2; Acts 2:22) Paul did apologetics at Lystra when he gave
evidence from that God existed and idolatry was wrong (Acts 14)
Mars Hill
ROADMAP
Types of Arguments• Inductive• Deductive
Bad Arguments• Formal Fallacies• Informal Fallacies
Tactics• Analysis
TYPES OF ARGUMENTS
Inductive Results in a high probability that
the conclusion is true. Common in science
Deductive Arguments If the premises are true,
and the structure is correct, the conclusion
must be true.
INDUCTIVE ARGUMENTS
Has premises and conclusion, but is probabilistic
100% of biological life forms that we know of depend on liquid water to exist.
Therefore, if we discover a new biological life form it will probably depend on liquid water to exist.
Used in the scientific method The conclusion is not certain, only
probable
STATISTICAL SYLLOGISM
Statistical Syllogism
P1: Most Greeks ate fish; P2: Socrates was a Greek; C: Therefore Socrates probably ate fish.
Similar in form to the deductive syllogism The conclusion is still not certain,
only probable
GENERALIZATION
Assumes a sample has the same attributes as a population
10% of the survey were Democrats
Therefore, 10% of people are Democrats
ANALOGY
Compares two situations Situations A and B are similar in properties
X and Y Situation A also has property Z Therefore, B probably has property Z as
well
May provide good evidence for a claim Is not conclusive
PREDICTION
Draws a conclusion about the future from the past Every time in the past that an apple has
been dropped, it has fallen. Therefore, if I drop an apple now, it will
probably fall
One of the foundational assumptions of science
DEDUCTIVE ARGUMENTS
Has premises and conclusion
P1: All men are mortal; P2: Socrates was a man; C: Therefore Socrates was mortal.
The conclusion is certain, but only if the premises are true and the structure is correct
√
VALIDITY AND SOUNDNESS
Validity An argument is valid if it has the
correct form Sound
An argument is sound if it is valid
and the premises are true
TYPES OF DEDUCTIVE REASONING
Categorical Logic Propositional Logic Modal Logic
CATEGORICAL LOGIC
First formalized by Aristotle Made up of simple statements Not all arguments can be translated
into this form But many can be translated into this form
CATEGORICAL LOGIC
4 types of statements All S are P No S are P Some S are P Some S are not P
Can be combined into groups of three called a syllogism
CATEGORICAL SYLLOGISM
Requires two kinds of premises Major Premise: All men are mortal; Minor Premise: Socrates was a man; Conclusion: Therefore Socrates was
mortal.
The premises must share a term (middle term)
P1: All men are mortal; P2: Socrates was a man; C: Therefore Socrates was mortal.
CATEGORICAL SYLLOGISMS
Not all combinations of terms are valid;
P1: All cats are mammals; P2: Oreo is a Cat; C: Therefore Oreo is a mammal.
P1: All mammals are animals; P2: some cats are animals; C: Therefore some cats are mammals.
X
√
PROPOSITIONAL LOGIC
The most basic logic dealing with conditionals If then statements, etc.
More powerful than simple categorical syllogisms 9 basic rules
RULE #1 MODUS PONENS
If P, then Q P Therefore, Q
Valid, example: If the ground is wet, it is raining The ground is wet Therefore it is raining
(this one is unsound because the premise is false)
√
RULE #2 MODUS TOLLENS
If P, then Q Not Q Therefore, not P
Valid, example: If it is raining, the ground is wet The ground is not wet Therefore it is not raining
(This one may be unsound as well)
√
RULE #3 HYPOTHETICAL SYLLOGISM
If P then Q If Q then R Therefore if P then R
Example If it is raining, the ground is wet If the ground is wet, the roads are slippery Therefore, if it is raining, the roads are
slippery
√
RULE #4 CONJUNCTION
P Q Therefore P and Q
Example John is a good student Mary is a good student Therefore John is a good student and Mary
is a good student
√
RULE #5 SIMPLIFICATION
P and Q Therefore P
Example John is a good student and Mary is a good
student Therefore John is a good student
√
RULE #6 ABSORPTION
If P then Q Therefore If P then P and Q
Example If it is raining, the road is wet Therefore if it is raining, it is raining and
the road is wet√
RULE #7 ADDITION
P Therefore P or Q
Example It is raining Therefore if it is raining or the sun is
shining√
RULE #8 DISJUNCTIVE SYLLOGISM
P or Q Not P Therefore, Q
Example It is either raining or the sun is shining It is not raining Therefore, the sun is shining
√
RULE #9 CONSTRUCTIVE DILEMMA
If P then Q and If R then S P or R Therefore, Q or S
Example If it is raining the streets are wet, and if it
is sunny the streets are dry It is either raining or sunny Therefore, the streets are wet or the
streets are dry
√
ROADMAP
Types of Arguments• Inductive• Deductive
Bad Arguments• Formal Fallacies• Informal Fallacies
Tactics• Analysis
FORMAL FALLACIES
Result from errors of logical form May have true conclusions But the conclusion does not follow from the
premises
INCORRECT CATEGORICAL SYLLOGISM Many types: Ex:
All communists are leftists. No conservatives are communists. Therefore, no conservatives are leftists.
Ex: All dogs are animals. No cats are dogs. Therefore, no cats are animals.
X
X
AFFIRMING THE CONSEQUENT
Improper modus ponens Ex:
If God exists, then objective morals and duties exist
Objective morals and duties do exist Therefore God exists
X
DENYING THE ANTECEDANT
Improper modus tollens Ex:
If God does not exist then objective values and duties do not exist
God does exist Therefore objective values and duties exist
X
INFORMAL FALLACIES
Mistakes in reasoning that arise from the content of the argument⁻ Ad hominem⁻ Red herring ⁻ Straw man⁻ Appeal to Authority⁻ Slippery Slope⁻ Weak Analogy⁻ Hasty Generalization
⁻ False Cause⁻ Appeal to
Ignorance⁻ Bandwagon⁻ Genetic Fallacy⁻ Begging the question
⁻ Appeal to Emotion⁻ Special pleading⁻ Equivocation⁻ Self refuting Statements
Meaning: “To the man” Favorite of politicians Ex:
"All politicians are liars, and you're just another politician. Therefore, you're a liar and your arguments are not to be trusted."
AD HOMINEM
X
An irrelevant fact intended to divert attention from the real issue
Therefore, if morality exists, then God must exist too!
Sure, but what about slavery in the Bible? That does not sound very moral to me…
Don’t take the bait!
RED HERRING
X
Misrepresenting your opponents position so it can be more easily defeated
“Here is the message that an imaginary 'intelligent design theorist‘ might broadcast to scientists: 'If you don't understand how something works, never mind: just give up and say God did it.” –Richard Dawkins
“one of the truly bad effects of religion is that it teaches us that it is a virtue to be satisfied with not understanding.” -Richard Dawkins
STRAW MAN
X
X
APPEAL TO ILLEGITIMATE AUTHORITY If an argument is based on authority, it
should be a legitimate authority, otherwise it is a bad argument
Ex: Biogeography gives very strong evidence for evolution. But Ray Comfort says evolution is false!
X
SLIPPERY SLOPE
Argues that by permitting A to occur, a far-fetched Z will occur. Only fallacious if Z is not a likely
consequence of A Ex:
Colin Closet asserts that if we allow same-sex couples to marry, then the next thing we know we'll be allowing people to marry their parents, their cars and even monkeys. –yourlogicalfallacy.com
X
WEAK ANALOGY
If using an inductive analogy, the analogy must be strong or the argument is fallacious
Ex: Cars and motor-boats both have engines and steering wheels. Cars have wheels Therefore boats must have wheels as well
X
HASTY GENERALIZATION
Drawing a conclusion about a whole group based on a few members of that group Not all generalizations are hasty
Ex: Both of the politicians I have met were liars Therefore, all politicians are liars
X
FALSE CAUSE
Post hoc ergo proctor hoc (After this therefore because of this) Correlation does not imply causation
Ex: Pointing to a fancy chart, Roger shows
how temperatures have been rising over the past few centuries, whilst at the same time the numbers of pirates have been decreasing; thus pirates cool the world and global warming is a hoax.
–yourlogicalfallacy.com
X
APPEAL TO IGNORANCE
Draws a conclusion from a lack of evidence Absence of evidence is not necessarily
evidence of absence
Ex: You arguments have failed to show that God
exists; Therefore, God must not exist.
X
BANDWAGON
Everyone knows that… Ex:
Everyone knows that Stephen Hawking disproved God…X
GENETIC FALLACY
Claiming a belief is false because you can explain why someone believes it “Why aren’t you a Hindu? Because you happen
to have been brought up in America, not in India. If you had been brought up in India, you’d be a Hindu. If you’d been brought up in Denmark at the time of the vikings, you’d be believing in Wotan and Thor. If you had been brought up in classical Greece you’d be believing in Zeus. if you had been brought up in central Africa, you’d be believing in the great Juju up the mountain.” –Richard Dawkins
X
BEGGING THE QUESTION
How do I know the Bible is true? Because the Bible says it is true, and I
believe it!X
ARGUMENT FROM EMOTION
An appeal to emotion
“they were religious, and that provided all the justification they needed to murder and destroy” –Richard Dawkins
“Imagine, with John Lennon, a world with no religion. Imagine no suicide bombers, no 9/11, no 7/7, no Crusades, no witch-hunts…” –Richard Dawkins
X
SPECIAL PLEADING
Exempting your claims from your own requirements Everything that exists has a cause God exists So what caused God? A: God doesn’t count because He’s uncaused!
X
EQUIVOCATION
Using the same word with two different meanings Define your terms!
SELF REFUTING STATEMENTS
The argument proves itself to be wrong
ROADMAP
Types of Arguments• Inductive• Deductive
Bad Arguments• Formal Fallacies• Informal Fallacies
Tactics• Analysis
ANALYZING ARGUMENTS
Arguments are rarely stated in simple syllogisms
We must take complex arguments and break them down into simple parts we can analyze
EXAMPLE 1
What would happen if we get down on our knees and pray to God in this way:
Dear God, almighty, all-powerful, all-loving creator of the universe, we pray to you to cure every case of cancer on this planet tonight. We pray in faith, knowing you will bless us as you describe in the Bible. In Jesus' name we pray, Amen.
We pray sincerely, will anything happen? No. Of course not
http://godisimaginary.com/i1.htm
ANALYSIS
What was the argument Maybe…
God promises to answer all prayers God didn’t give me what I prayed for Therefore God does not exist
ANALYSIS
False premise
God promises to answer all prayers
Christians do not necessarily believe this, so the argument is unsound
ANALYSIS
What was the argument?
If I pray and God exists, then God will answer my prayer
I prayed God didn’t answer my prayer Therefore God does not exist
This is valid, but Christians may disagree with the premises
EXAMPLE 2
“We could learn to live with people from all races and not immediately hating and wanting to kill someone just because they believe in a different god.Yes, a world without God would be a far better, friendlier and happier place. A world without religion would also be a safer place for innocent children, who have been abused by the religious-lot for centuries and continue to be abused.”
–god-does-not-exist.org
ANALYSIS
This argument was an argument from emotion
It did not provide facts or evidence It only claimed that religion harms
children
EXAMPLE 3
To understand why "God does not exist" can be a legitimate scientific statement, it's important to understand what the statement means in the context of science. When a scientist says "God does not exist," they mean something similar to when they say "aether does not exist," "psychic powers do not exist," or "life does not exist on the moon."
All such statements are casual short-hand for a more elaborate and technical statement: "this alleged entity has no place in any scientific equations, plays no role in any scientific explanations, cannot be used to predict any events, does not describe any thing or force that has yet been detected, and there are no models of the universe in which its presence is either required, productive, or useful."
ANALYSIS
What is the argument: There is no empirical evidence that can
only be attributed to God If God exists, then he will produce
empirical evidence Therefore God does not exist.
ANALYSIS
What is the argument: There is no empirical evidence that can
only be attributed to God If God exists, then he will produce
empirical evidence Therefore God does not exist.
This is deductively valid (maybe) But is it True?
√
ANALYSIS
There is no empirical evidence that can only be attributed to God
If God exists, then he will produce empirical evidence
Therefore God does not exist.
We would disagree with the first premise, and maybe even the second premise!
XX
CONCLUSION
Logic can be a useful tool in understanding arguments
But arguments are rarely in logical form Therefore, it is useful to be able to
analyze arguments in logical form to find errors
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