In apologetics, an argument is composed of a set of valid premises followed by a logical conclusion.
I'm not going to be making the Armani suit, I'm going to be the clothes purveyor to Target.' Instead, he suggests that there's somehow no valid premise for expensive wines".
Finally, they involve logical inference, such that conclusions are drawn from valid premises.
Most plausibly, perhaps, Aristotle's complete and incomplete syllogisms taken together are understood as formally valid premise-conclusion arguments; and his complete and completed syllogisms taken together as (sound) deductions.
(Of course, there further two alternatives are crucial to Lewis' overall analysis of the passage: essentially, Lewis suggests that Anselm equivocates between an invalid argument with plausible premises and a valid argument with question-begging premises. In this respect, Lewis' analysis is quite different from the other analyses currently under discussion).
"Did you see the contrast in the numbers of heads of state at the Paris and Ankara memorial ceremonies?" "Did you know that Tintin, the symbol of the Brussels solidarity, has a racist past?" "Maybe Belgium's imperialist history in the Congo should give it pause when choosing its symbols?" All these questions make a valid point, but their premise is flawed.
In a valid argument, if the premises are true, the conclusion must be true as well.
Truth is preserved in a valid inference from the premises to the conclusion (or the conclusions in a multiple-conclusion setting).
However, it is unclear, and is left unclear, what score to assign to a valid argument with false premises: how good should we consider such an argument?
An inference is monotonic iff adding arbitrary new premises to a valid argument does not affect its validity.
