Now we are ready to focus our attention on the main problem of logic, the capturing of consequence. Let us first point out the obvious fact that consequence is one side of the coin, the other side of which is necessary truth; and that we can equivalently talk of capturing necessary truth instead of capturing consequence. Each instance of consequence, if articulated, gives rise to a necessarily true statement: to say that it is valid to infer a statement class="EmphasisTypeItalic ">S from statements S ₁ ,...,S _n to say that the statement If (it is the case that) S ₁ and ... and S _n , then (it is the case that) S, or, regimented into symbolic notation, (S ₁ ∧ ... ∧ S _n )→S, is necessarily true. Thus the valid inference (16) can be expressed as the necessarily true statement (17); similarly, the validity of (18) is tantamount to the necessary truth of (19)¹⁷.