 We are now equipped state another, more specific gap in the reductionist argument. Whilst Ben Vorlich and Ben Vane’s having the heights they do avoids the need to admit the existence of a thick (internal) relation that Ben Vorlich bears to Ben Vane, this doesn’t avoid the need to admit the existence of a thin (internal) relation. This is because we need to explain why Ben Vorlich’s having the height it does (3094 ft) and Ben Vane’s having the height it does (3004 ft) entails that Ben Vorlich is taller than Ben Vane. The answer is that the thin relation being greater than holds between the number of feet in height that Ben Vorlich has and the number of feet in height that Ben Vane has (Russell 1903: §214; Bigelow &amp; Pargetter 1990: 55–6. So internal relations may not (in general) be required to perform the role of truth-makers for comparative claims. Nonetheless thin internal relations may perform an indispensable role in explaining why the truth-makers for comparative claims are equipped to make such claims true, rather than leaving this a matter of brute inexplicable necessity—because, in this case, the heights of the mountains in question lie in a certain relation of proportion to one another. Similarly Ben Vorlich’s being taller than Ben Vane’s supervenes upon their heights but this is only intelligible because the height of Ben Vorlich is larger than the height of Ben Vane.