 The last point suggests that only a complex entity that “contains” Socrates as well as the property of being wise is a candidate for the truth-maker role. The mereological sum of Socrates and being wise, that is, the whole that has only Socrates and wisdom as parts, satisfies this condition, yet it cannot fulfill the truth-maker role. If Socrates and wisdom exist, their mereological sum exists. Hence, the sum exists whether it is true that Socrates is wise or not. For similar reasons the set that contains only Socrates and being wise cannot be the truth-maker of the thought that Socrates is wise. Armstrong concludes that only the fact that Socrates is wise that “ties” Socrates and being wise makes it true that Socrates is wise (see Armstrong 1997: 118).