 The Islamic mathematician Ibn Qurrah (9th century CE) took a decidedly infinitistic attitude and argued, against the Aristotelian commentators, that there can be different sizes of infinity (see Rashed 2009). He claimed, for instance, that the odd and the even numbers have the same size, but that the multiples of three are 1/3 of the total number of natural numbers. Contrary to what has been claimed in the literature, his intuition was not that the even numbers and the odd numbers have the same size because there is a one-to-one correspondence between them. Rather we have a “frequentist” intuition: every even number is followed by an odd number; multiples of three appear every three numbers, etc. We find a similar position in Grosseteste’s treatise De Luce (see Mancosu 2009, 2016 for an overview of the historical developments and further references).