I don't quite understand this :
"As it turns out, all valid arguments can be restated as tautologies - that is, hypothetical statements in which the antecedent is the conjunction of the premises and the consequent the conclusion. In other words, every valid argument may be articulated as a statement of this form : 'If W,X,Y are true, then C is true', where W, X and Y are the argument's premises and C is its conclusion. When any valid argument is substituted in this form, a tautology results." - Julian Baggini, The Philosopher's Toolkit
How is this a tautology? Isn't a tautology something that is necessarily true regardless of the truth values assigned to W,X and Y (in this case)?
Or is the author here referring to "tautologies" in a different sense? (where it does not add any informative value as it repeats the meaning of something which is already understood)