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I'm fairly new to logic.

What I've surmised from the book I'm reading is that

  • Logic is the science of evaluating arguments
  • Arguments are composed of statements
  • Statements are sentences that can be evaluated as true or false

However, When I ask questions about it or read answers in certain online forums - including but not limited to SE - occasionally I come across an answer something along the lines of

In logic, "truth" is not such a useful concept.

My assumption was that truth is integral to argumentation because the atomic elements of an argument are inherently grounded in truth and falsity. Basically, I thought of logic as an aide in determining whether a conclusion is true or not. But, I'm wondering if it's more about evaluating whether a conclusion CAN BE TRUE based on the structure of the argument.

How is truth related to logic?

How is truth related to our objective in using logic?

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The authors of forall x: Calgary Remix claim there are two ways for an argument to go wrong and logic is usually concerned with the second of those two ways (page 8):

For any argument, there are two ways that it might go wrong:

  • One or more of the premises might be false.

  • The conclusion might not follow from the premises.

To determine whether or not the premises of an argument are true is often a very important matter. However, that is normally a task best left to experts in the field: as it might be, historians, scientists, or whomever. In our role as logicians, we are more concerned with arguments in general. So we are (usually) more concerned with the second way in which arguments can go wrong.

This study of whether the conclusion follows from the premises leads to the concept of an argument being "valid" which they also define (page 8):

An argument is valid if and only if it is impossible for all of the premises to be true and the conclusion false.

Now consider the questions:

How is truth related to logic?

Based on the above description of the two ways an argument can go wrong, logicians are more concerned with identifying valid arguments, not true arguments.

How is truth related to our objective in using logic?

Based on the above definition of validity, if logicians show that an argument is valid and if subject-matter experts show that the premises are all true, then the conclusion of the argument is also true.


Reference

P. D. Magnus, Tim Button with additions by J. Robert Loftis remixed and revised by Aaron Thomas-Bolduc, Richard Zach, forallx Calgary Remix: An Introduction to Formal Logic, Winter 2018. http://forallx.openlogicproject.org/

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