  Like Albert, Aquinas too suggests that there is a close connection between relational accidents and their foundations. Following Albert’s terminology, he suggests that in virtue of possessing a specific height or quantity, an individual such as Socrates is potentially equal to all those who have the same height, and potentially unequal to—that is, shorter or taller than—all those with a different height (In V Phys., lect. 3, n. 8). Like Albert, moreover, Aquinas says that such an individual can come to be actually equal (or unequal) to another solely in virtue of a change in that other, and concludes from this that relations must be in their foundations as in a root (in radice) (In V Phys., lect. 3, n. 8). On some interpretations, Aquinas’s metaphor can be explicated by saying that although relations and their foundations differ formally—that is, involve different accidental forms or properties—nonetheless their act of being (esse) is the same. Thus, when Socrates comes to be shorter than Simmias as a result of Simmias’s growth, Socrates does not undergo a change properly speaking, since he does not acquire any new act of being. Rather, the “old” act of being of his height (sometimes referred to as the ‘esse-in’ of the relation) merely acquires a new determination (sometimes referred to as the ‘esse-ad’ of the relation), in this case  to  Simmias.[29]