The analyses conducted in previous chapters have shown that Brentano's descriptive psychology, in all its ramifications, always maintained a twofold valence between theoretical and empirical. In the last years of Brentano's life, these two aspects merged into a metaphysical theory which on the one hand constituted a philosophical variation (in effect, a reversal) of Aristotle's position on the problem of substance and accidents, which was due to specification of the concept of thing, while on the other it maintained the scientific, empirical and experimental thrust of the Appendixes to Psychology II and the various texts collected in Psychology III.