A not uncommon conclusion of philosophers studying the conceptual foundations of measurement is that scales of measurement, though subject to requirements of consistency, convenience, and simplicity, are essentially based upon conventions, and thus cannot be said to refer to relationships among existing quantities. Brian Ellis, for example, in one of. the most searching contemporary analyses of measurement concepts, claims that

Some aspects of measurement are clearly conventional in the strong sense of resting on essentially arbitrary agreements. Thus to ask which of the scales of temperature, Centigrade or Fahrenheit, is the ‘true’ scale would be like asking which are the true words for the first three integers - ‘one, two, three’ or ‘eins, zwei, drei’.