||An alleged law of nature—like Newton's law of gravitation—is said to be a ceteris paribus law if it does not hold under certain circumstances but only ‘when other things are equal’. Typical examples are: ‘provided the supply remains constant, the price of a product increases with growing demand, ceteris paribus’, ‘all bodies fall with the same speed, ceteris paribus’, ‘haemoglobin binds O2, ceteris paribus’. There is, however, an inherent tension in the notion of a ceteris paribus law: on the one hand, laws are said to be strict universal regularities, on the other hand, the proviso clause seems to allow for certain exceptions. Moreover, in the current debate on ceteris paribus laws fervent opponents to the whole idea of law statements with proviso clauses point out that no good sense can be made of a statement like ‘All Fs are Gs, ceteris paribus’. Such a phrase, so they say, is either tautologous like ‘All Fs are Gs, unless not’ or it stands for a proposition like ‘All Fs which are also… are Gs’ the gap of which we are unable to close. Many of those who argue in favour of the idea of ceteris paribus laws, however, not only claim that a proper analysis of what the proviso clause is supposed to mean can be given but even that all laws are of ceteris paribus character.