 Take a sentence in the indicative mood, suitable for making a statement: “We’ll be home by ten”, “Tom cooked the dinner”. Attach a conditional clause to it, and you have a sentence which makes a conditional statement: “We’ll be home by ten if the train is on time”, “If Mary didn’t cook the dinner, Tom cooked it”. A conditional sentence “If \(A, C\)” or “\(C\) if \(A\)” thus has two contained sentences or sentence-like clauses. \(A\) is called the antecedent, \(C\) the consequent. If you understand \(A\) and \(C\), and you have mastered the conditional construction (as we all do at an early age), you understand “If \(A, C\)”. What does “if” mean? Consulting the dictionary yields “on condition that; provided that; supposing that”. These are adequate synonyms. But we want more than synonyms. A theory of conditionals aims to give an account of the conditional construction which explains when conditional judgements are acceptable, which inferences involving conditionals are good inferences, and why this linguistic construction is so important. Despite intensive work of great ingenuity, this remains a highly controversial subject. 