I am currently finding it hard to understand deductive arguments. I am taking a module called 'Effective Reasoning'. I've been finding it so hard to understand some things (as simple as this).
I decided to read the provided textbook to understand better (Salmon Merrillee - Introduction to logic and critical thinking) but still have some questions.
The definition of a deductive argument according to the book: "In a deductive argument if the premisses are true the conclusion cannot be false".
I am a little confused with the part where it says that the conclusion cannot be false if the premises are true. Consider a deductive argument with a true premise, then what they are saying is that whatever the conclusion is, it will be true (?) then wouldn't any conclusion be true - even one that is obviously false? I'm sure they do not mean it this way, but can someone define it in simpler terms?
Given some examples:
How exactly do we check if a premise guarantees the truth? E.g.
Jack is a bachelor
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(Conclusion) Jack has no wife
Is this how I should approach the argument?: Look at the premise "Jack is a bachelor" and derive the meaning: bachelor means "a man who is not and has never been married." (from dictionary)
And then I look at the conclusion "Jack has no wife". This matches the premise, hence it is a deductive argument?
And what about this example?
Whatever is done as an expression of love is morally acceptable.
Mrs. X, who believed her child's soul was possessed by demons that
could be driven out only by beating the child, beat her child severely
because she loved him.
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(Concl.) Mrs. X did something morally acceptable when she beat the child.
According to the original definition of a deductive argument, I would think that the above is a sound argument.
Why is the sentence false? Considering the first premise says that:
1)Whatever is done as an expression of love is morally acceptable.
and the second premise says that Mrs X. beat her child .... because she loved him.
However, the textbook shows this, which I do not quite understand.