It follows that there are, strictly speaking, only two _substances_, matter and spirit: all particular things result from the composition in varying degrees of these two--are therefore mere "accidents," and have no abiding reality. Bruno joins issue in this with the Peripatetics, to whom the "real man," for example, is a composite of body and soul, or the true soul is the perfection or actualisation of the living body, or is a resultant from a certain harmony of form and of limbs.[259] Death or dissolution would mean to them the loss of their being; whereas neither "body nor soul need fear death, for both matter and form are constant abiding principles."[260] This theory of substance and of immortality was regarded by Bruno as one of the cardinal points of his philosophy,[261] and one in which he differed most widely from Aristotle, as interpreted by him, and from the Aristotelians. Its statement, and the criticism of the Peripatetics, occur again and again throughout the works, and he believed the removal from man of the fear of death to be one of the greatest results of his teaching.--"This spirit, being persistent along with matter--and these being the one and the other indissoluble, it is impossible that anything should in any respect see corruption or come to death, in its substance, although in certain accidents everything changes face, and passes now into one composition, now into another, through now one disposition, now another, leaving off or taking up now this now that existence. Aristotelians, Platonists, and other sophists have not understood what the substance of things is. In natural things that which they call substance, apart from matter, is pure accident. When we know what _form_ really is, we know what is life and what is death; and, the vain and puerile fear of the latter passing from us, we experience some of that blessedness which our philosophy brings with it, inasmuch as it lifts the dark veil of foolish sentiment concerning Orcus and the insatiable Charon, that wrests from us or empoisons all that is sweetest in our lives."[262] There is a certain ambiguity in the description of substance. Whether is the spiritual unity which is placed over against matter itself substance, or is it rather the particular souls which are part of it, and which are thus immortal, changing only the form of composition into which they enter? In this dialogue it seems Bruno is speaking only of the world-soul,[263] but in later works, especially in the _Spaccio_ and _De Minimo_, the substantiality and immortality of the individual soul are categorically asserted. In the _Causa_ however, Bruno maintains quite clearly the substantiality of the universal soul alone, the finite individual being merely one of the modes of its determination in matter.[264]