I am grateful to Professor d’Aspremont for his interesting and courteous response to my somewhat critical piece. I think we agree . . . that there is plenty on which we agree to differ! However, may I mention a few points?
A minor linguistic matter: the terms ‘the logic of sources’ and ‘the logic of interpretation’ seem to me unfortunate. I trust that Prof. d’Aspremont will agree that the rules of logic, or if you like of logical argument, are surely identical whatever the subject under discussion. The postulates and the facts are unique to the context and the problem examined, but to arrive at an intellectually correct result, the reasoning processes must follow the universal rules of logic; the expressions quoted seem to undermine this universality.
Prof. d’Aspremont does not find my use of the concept of opposability helpful. Maybe my point will be clearer if expressed in this way: in the relevant part of the ICJ Whaling judgment, the Court was, in his view engaged in a process of interpretation, but applied to it the intellectual approach appropriate to a problem of sources. But was it a process of interpretation? Before the Court could enquire into what exactly were the obligations of Japan under the Whaling Convention as interpreted by the challenged resolution – a matter of interpretation – it had to decide whether the resolution was relevant at all – a question of sources (consent to a treaty-instrument). If the resolution was relevant, its effect on the reading of the Convention would be a matter of interpretation; but that stage was never reached.
Prof. d’Aspremont denies that he is ‘thinking from the Bench’; but surely whenever a scholar criticises a judicial decision, he is in effect saying ‘This is what the Court ought to have said: this is what my dissenting opinion would have said had I been among the judges?’ And to my mind this is so whether the critic is saying ‘The Court was wrong on its own premises’, or contending that ‘The matter should have been approached in a different way, viz. . . .’