He must have gone to the pub, because the interview is cancelled
The arguer states in the conclusion that something has happened and supports this claim by stating that an alternative course of events did not happen. Since the argument fits the form q is T, because r is T, it can be identified as a second-order subject argument. In this specific case, q is instantiated by ‘he has gone to the pub’ and r by ‘the interview is cancelled’.
He has gone to the pub (q) is true (T), because the interview is cancelled (r) is true (T)
Second-order subject arguments are further differentiated by identifying the types of statement in the conclusion and the premise. In this case, both are statements of (logical) value, which means that we are dealing with a second-order subject argument supporting a value with a value (2 sub VV).
The trivial name of second-order subject arguments is derived from the characterization of the relationship between the subjects r and q. In this example, the argument draws on the disjunction between not-r and q: either the interview is not cancelled or he went to the pub (but not both). We can therefore call such an argument an ‘argument from disjunctives’.