Apologetics, Logic , And reasoning

Logically Captain… Presented by Ratio Christi TAMU Apologetics, Logic, And reasoning

Greek (άπολογία) Apologetics

God commandsthe use of Reason. • “but sanctify Christ as Lord in your hearts, always being ready to make a defenseto 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) Why Apologetics?

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! Is Apologetics arguing?

There have been many objections to apologetics from Christians: Objections to apologetics

"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 Not 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. The Bible Does Need to Be Defended?

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) Jesus Refused to do Signs for Evil Men

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 Paul Was Unsuccessful In His Use of Reason on Mars Hill

“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. Only Faith, not Reason, Can Please God

“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. God Can't be Known by Human Reason

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 eitherthe 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. Only the Holy Spirit Can Bring Salvation

Greek (λογική) 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 Logic

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 probablegiven the premises. What is a Formal Argument √

Mostly, the Bible was not written for unbelievers but for believers. • Apologetics ISused 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 Apologetics is not Used in the Bible?

Roadmap

Inductive • Results in a high probability that the conclusion is true. • Common in science Types of Arguments • Deductive Arguments • If the premises are true, and the structure is correct, the conclusion must be true.

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 Inductive Arguments

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 Statistical Syllogism

Assumes a sample has the same attributes as a population • 10% of the survey were Democrats • Therefore, 10% of people are Democrats Generalization

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 Analogy

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 Prediction

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 Deductive Arguments √

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 Validity and Soundness

Categorical Logic • Propositional Logic • Modal Logic Types of deductive Reasoning

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 Sare P • No Sare P • Some Sare P • Some Sare not P • Can be combined into groups of three called a syllogism Categorical Logic

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 (middleterm) • P1: All menare mortal; • P2: Socrateswas a man; • C: Therefore Socrateswas mortal. Categorical Syllogism

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. Categorical Syllogisms √ X

The most basic logic dealing with conditionals • If then statements, etc. • More powerful than simple categorical syllogisms • 9 basic rules Propositional Logic

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 #1 Modus Ponens √

If P, then Q • NotQ • Therefore, notP • Valid, example: • If it is raining, the ground is wet • The ground isnotwet • Therefore itisnotraining • (This one may be unsound as well) Rule #2 Modus Tollens √

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 #3 Hypothetical Syllogism √

P • Q • Therefore P and Q • Example • John is a good student • Mary is a good student • Therefore John is a good studentand Mary is a good student Rule #4 Conjunction √

Pand Q • Therefore P • Example • John is a good studentand Mary is a good student • Therefore John is a good student Rule #5 Simplification √

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 rainingand the road is wet Rule #6 Absorption √

P • Therefore P or Q • Example • It is raining • Therefore if it is raining or the sun is shining Rule #7 Addition √

P or Q • NotP • Therefore, Q • Example • It is either rainingor the sun is shining • It is not raining • Therefore,the sun is shining Rule #8 Disjunctive Syllogism √

If Pthen Q and If Rthen S • Por R • Therefore, Q or S • Example • If it is rainingthe streets are wet, and if it is sunnythe streets are dry • It is either rainingor sunny • Therefore, the streets are wet or the streets are dry Rule #9 Constructive Dilemma √

Roadmap

Result from errors of logical form • May have true conclusions • But the conclusion does not follow from the premises Formal Fallacies

Many types: • Ex: • All communistsare leftists. • No conservativesare communists. • Therefore, no conservativesare leftists. • Ex: • All dogsare animals. • No catsare dogs. • Therefore, no catsare animals. Incorrect categorical syllogism X X

Improper modus ponens • Ex: • If God exists, then objective morals and duties exist • Objective morals and duties do exist • Therefore God exists Affirming the consequent X

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 Denying the Antecedant X

Apologetics, Logic , And reasoning