Critical Thinking Part 1 – Logic & Argument


What is an argument?

What is logic?

[NOTE:  Part 2 – The Theology of Argument]

That’s what will be covered in this post.

If this series works out the way I hope, I shall be covering the following:

  • Categorical Logic (Logic of Classes) – emphasizes class relationships
  • Categorical Logic is the study of class relationships and the usage of the words ALL, SOME, and NOT in relating classes

Example:  All Irishmen are drunkards.

venn diagram irishmen

All in the set called Irishmen are contained in the set drunkards.

  • Propositional logic:  emphasize connectives between propositions not classes
  • Propositional logic is the study of the relationships between propositions and the usage of the words AND, OR, and IF-THEN.

In studying logic we shall master the Logician’s use of:  SOME, ALL, NOT, AND, OR, & IF-THEN

That’s it.  Now we can do a lot with those seven words, but that is all we will be covering.

ARGUMENT

An argument is a group of propositions, wherein the truth of one of those propositions is asserted on the basis of the evidence furnished by the other propositions.   In an argument evidence bearing statements (premises) are supposed  lead to the conclusion.  The conclusion is inferred by the evidence bearing statements (premises).  The purpose of an argument is to get us to agree with the arguer.

We will be studying deductive arguments, inductive arguments, and perhaps a few more varieties.

Deductive Argument – an argument whose conclusion necessarily follows from its premises.

  1. All men are mortal.
  2. Socrates is a man.
  3. Therefore, Socrates is mortal.

1 & 2 are the premises and 3 is the conclusion.  If all men are mortal, and if Socrates is a man, then it necessarily follows that Socrates is also mortal.

Inductive Argument – an argument whose conclusion is claimed to follow with a certain probability from the premises

  • All the ravens I’ve seen so far are black
  • If I see a raven tomorrow it will probably be black

It could be that you might see a white raven tomorrow.  But if all the ravens you have seen so far are black, then it is more probable that you will see a black raven tomorrow as well.

LOGIC

Logic is the study of inferring or we can say that logic studies inference patterns.  Therefore logic is the study of argumentation.  So what do we mean by the word argument?  An argument in this context does not mean disagreement nor contention.  But in the popular mind when one hears the word argument one tends to think argumentative.  But argumentative does not mean argument.  We could agree on the same thing and still engage in argumentation about it to sharpen our understanding of a certain subject.  It would be better to think contentiousness instead of argumentative.  While it is a Christian virtue to master argumentation, it is not a Christian virtue to be contentious.

But what is necessary for an argument?  For an argument to be made it requires that something be asserted.  Without an assertion, there is no argument.  Take the following sentence:  If stealing from people is a sin, then when I steal from someone I sin.  Is that an argument?  Have I asserted anything?  No.  What about this statement  Stealing from people is a sin, so when I steal from someone I sin.  That is an argument because I have asserted that stealing from people is a sin.  Remember, WITHOUT AN ASSERTION THERE IS NO ARGUMENT.

OK so you know that an argument contains premises and a conclusion.  But how do you determine which is which?  After all, the Bible isn’t setup in neat little syllogisms for us to memorize.  Premises are usually preceded by such words as inasmuch as, on the ground that, for, since, because, and similar words.  Conclusions are usually preceded by such words as we may infer/conclude that, thus, so, consequently, therefore ( favorite of St. Paul), it follows that, hence, and other such words.  To identify the premises or conclusion in an argument you must learn to look for indicator words.  In the follow passage from Romans 2 finding the Premises and the Conclusions is fairly easy:

  24For the name of God is blasphemed among the Gentiles through you, as it is written.  25For circumcision verily profiteth, if thou keep the law: but if thou be a breaker of the law, thy circumcision is made uncircumcision.  26Therefore if the uncircumcision keep the righteousness of the law, shall not his uncircumcision be counted for circumcision?

But indicator words are not always available.  So how do we distinguish the premises from the conclusion when the text provides no indicator words?  We must ask ourselves, what is being argued for in this passage?  Try this commonly heard phrase when fishing:

There fish aren’t biting in this lake.  I haven’t caught one all day.

In the above, the first sentence is the conclusion and the second is the premise.  How do we know?  Because it is being argued that the fish aren’t in this lake.  And why not, because our hapless fisherman has yet to catch one.  A better case for dynamite fishing has never been made.  So remember, if the indicator words are not present in an argument, try to determine what the point of the argument is and that will be the conclusion.  Then whatever is left over will be the premises.

Sometimes when reading a passage you may not be reading an argument at all.  You could simply be reading an explanation for why someone took a course of action.  You could be reading a biographical anecdote.  Or you may be reading a Windows instruction manual.  I feel sorry for you if it is the latter.  If you cannot quickly determine whether or not a passage is an argument, then ask yourself what is the main purpose?  Is it to inform, entertain, explain?  Or is it to persuade?  If the passage is attempting to persuade you, then you are reading an argument.

Part 2 will cover the Theology of Argument.

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2 responses to “Critical Thinking Part 1 – Logic & Argument

  1. Pingback: Critical Thinking Part 2 – The Theology of Argument | The Biblical Thinker·

  2. Pingback: Apologetics 101 – Inconsistency | The Biblical Thinker·

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