body and social situation. Personal identity may be explained without accepting a spiritual agent as subject of mental activity. Associative connection between life episodes is necessary and sufficient for the maintenance of a united selfhood. Personal character and memories can persist after radical mutation of the body. Irreducible concepts Two irreducible concepts encountered in substance theory are the bare particular and inherence. Bare particular In substance theory, a bare particular of an object is the element without which the object would not exist, that is, its substance, which exists independently from its properties, even if it is impossible for it to lack properties entirely. It is "bare" because it is considered without its properties and "particular" because it is not abstract. The properties that the substance has are said to inhere in the substance. Inherence Another primitive concept in substance theory is the inherence of properties within a substance. For example, in the sentence, "The apple is red" substance theory says that red inheres in the apple. Substance theory takes the meaning of an apple having the property of redness to be understood, and likewise that of a property's inherence in substance, which is similar to, but not identical with, being part of the substance. The inverse relation is participation. Thus in the example above, just as red inheres in the apple, so the apple participates in red. Arguments supporting the theory Two common arguments supporting substance theory are the argument from grammar and the argument from conception. Argument from grammar The argument from grammar uses traditional grammar to support substance theory. For example, the sentence "Snow is white" contains a grammatical subject "snow" and the predicate "is white", thereby asserting snow is white. The argument holds that it makes no grammatical sense to speak of "whiteness" disembodied, without asserting that snow or something else is white. Meaningful assertions are formed by virtue of a grammatical subject, of which properties may be predicated, and in substance theory, such assertions are made with regard to a substance. Bundle theory rejects the argument from grammar on the basis that a grammatical subject does not necessarily refer to a metaphysical subject. Bundle theory, for example, maintains that the grammatical subject of a statement refers to its properties. For example, a bundle theorist understands the grammatical subject of the sentence, "Snow is white", to be a bundle of properties such as white. Accordingly, one