 Ockham claims that, although non-reciprocal relatives of identity always supposit for that for which their antecedent supposits, those whose antecedent is a general term occurring with personal supposition can never be replaced by their antecedent and result in an equivalent proposition. For example, ‘A man runs and he disputes’ is not convertible with ‘A man runs and a man disputes’. Buridan has two rules to explain what is happening (Summulae, tr. Klima pp. 283–4):