A valid argument is not necessarily logical and a logical argument is not necessarily valid.

What do you mean by the word "logical"?

Do you mean "of logic"?

One can have a valid logical argument based on a false premise, which **invalidates** the argument.

The truth or otherwise of a premise does not itself invalidate an argument.

All dogs are cats

All cats are mice

Therefore all dogs are mice.

This is a valid argument - it is impossible for the premises to be true and the conclusion to be false.

As you can see, it has no bearing on our reality.

The premises are untrue, the conclusion untrue, as far as our world goes.

But if there was a world where the premises were true, it would be impossible for the conclusion to be false.

That is why the argument is valid.

So validity doesn't mean that the premises

*are* true, only that if we accept the premises as true then it is impossible for the conclusion to be false.

An untrue premise in an otherwise valid argument makes the argument unsound.

So my example above is rather unsound.

You cannot cherry-pick the argument and parse it into logically valid and logically invalid parts.

Well, you can, especially if there happen to be irrelevant premises.

But that was not the reason I did so, but rather to show that on the face of it, by doing so, you might conclude that the argument was invalid.

A valid logical argument either yields a valid logical result of "true" or "not true".

No, a valid logical argument preserves the truth from premises to conclusion.

I.e. it is valid if it is impossible for the premises to be true yet the conclusion false.

An invalid logical argument always yields a result of "not true".

I'm somewhat unsure of what you mean by "result of true or not true".

Do you mean that you think in an invalid logical argument the conclusion is always not true / false?

If so, the argument above has a false conclusion (unless you think dogs are mice??) but it is valid.

And if anyone wishes to dispute this, you can begin by explaining how an elephant can logically be a squid or a giraffe at the same time.

It can't.

But that doesn't make the argument invalid.

Being two things at once is also quite possible: one can be a supporter of a football team and a member of the Republican party.

In logical arguments, validity is all about the preservation of truth through the form of the argument.

Anything to do with how the premises stack up in reality is a matter of soundness (assuming the argument valid).

Therefore, somewhere in the proposition there is a logical flaw, which invalidates the argument. And we know where that happens, no?

The argument is a pile of hooey, for sure, and useless, because it has contradictory premises.

But it is valid.

But it's validity in this case is nothing to do with the deductive relationship between premises and conclusion but because the argument is truth preserving.

In this instance it is truth preserving precisely because the premises can never all be true.

Joe is an elephant and therefore NOT a squid or a giraffe.

Therefore the answer that Joe is a giraffe is logically false (not true). He is an elephant.

Out of curiosity, why are you going with that particular premise and not the one that says that Joe is either a squid or a giraffe?