 For Buridan, a formal consequence holds by the principle of uniform substitution. It is valid for any uniform substitution of its categorematic terms. A syllogism is a special kind of formal consequence since it requires for its validity that terms be conjoined across sentences. How the principle of uniform substitution is supposed to work here is a bit tricky and forces him to bring into play his general semantics as well as the notion of distribution. To spell out the relation of their terms and hence the validity of the first figure syllogisms, he reformulates the traditional dici de omni et nullo rules (see King 1985: 71):