  However, there the connection between consequence and the conditional contains one extra factor. Not only is there the turnstile, for logical consequence, and the conditional, encoding consequence inside the language of propositions, there is also the comma, indicating the combination of premises. We have read “\(p, q \vdash r\)” as “\(r\) follows from \(p\) together with \(q\)”. To combine premises is to have a way to take them together. But how can we take them together? It turns out that there are different ways to do so, and so, different substructural logics. The behaviour of premise combination varies as the behaviour of the conditional varies. In this introduction we will consider some examples of this.