 These accounts can get quite technical, but the basic idea is relatively easy to understand. Since, on these accounts, concrete mass expressions refer to mereological sums, a sentence such as “Snow is white” is understood to mean that there is a sum of all the snow (flakes, bits, balls, etc.), and that this sum is part of the fusion of all the white things (Quine 1960, ch. 20). A sentence such as “The water is in the tub” gets cashed out to mean that there is a fusion of water molecules which is in the tub. While there are many permutations on this strategy, sum theorists will, whenever possible, paraphrase away talk of stuffs and talk instead of sums, where sums satisfy the constraints of Thinghood and do not contradict Thing Theory (TT) as outlined in  1.1.