When ancient philosophers describe the fate of the soul or the human being after death, in which cases should we attribute to them a theory of immortality? When their texts describe people – or their souls, parts, or possessions – as being or becoming ‘immortal’, what does the word mean? The research brought together here explores these questions. Whether or not we should stipulate the meaning of immortality depends on which question we are addressing. The first question is about our own use of the words ‘immortal’ and ‘immortality’ when reading and trying to understand ancient theories, and here it may be appropriate to set down that ‘immortal’ means, for example, everlasting. That is how Phillip Horky understands ‘immortal’ and ‘immortality’ in his chapter on whether Pythagorean theories of reincarnation (or, as it is also called, the transmigration of souls) require souls to be everlasting.

Whereas in the previous chapters the influence of law on philosophy is brought up, this chapter deals the influence of law on philosophy, with regard to method. Already within early Hellenistic philosophy a shift of focus can be discerned from a virtue-centered to an action-orientated approach: in the 3rd century BCE the early Stoics had become interested in questions about the ‘appropriate actions’ that can be derived from these virtues. In the 2nd century BCE, inspired by the Roman jurists, the Roman Stoics became interested in the concrete applications of such actions or – put differently – introduced casuistry into philosophy.

In this contribution, I offer a study of what I take to be the core argument of Augustine’s De Immortalitate Animae, a series of notes that, once reworked into dialogue form, were designed to form book III of his Soliloquies. Taking his starting-point from the premise that a structured body of truths (disciplina), e.g. geometry or arithmetic, always exists, and that it must inseparably exist in a subject, i.e. the soul, Augustine claims to deduce that the soul is immortal. This argument contrasts interestingly with the arguments from recollection in Plato’s Phaedo and Meno, which begin from the premise that the soul’s innate knowledge could not have been acquired in a person’s lifetime. Innate knowledge, however, is no guarantee of the soul’s eternal pre- or post-existence, since the soul could have come to be in time with its knowledge already present. Augustine’s method of argument, which makes the soul’s immortality depend on the eternity of truth, avoids this objection, only to face other serious difficulties of which he himself was well aware. I will discuss a number of these problems, before finally considering whether the concept of ‘reason’ (ratio) in chapters 10-11 of his embryonic treatise can establish a firm link between truth and immortality.

It is clear from his extensive biological writings that Aristotle was deeply interested in life, including a vast range of living things, their parts, lifestyles, life processes, and environments. How are life and living beings, extensively described and explained in the biological writings, reflected in Aristotle’s ontology, his understanding of being? My question is prompted in part by the fact that some of Aristotle’s most important metaphysical concepts apply equally to living beings (animals) and to non-living beings (artifacts). In this chapter I develop an account of the theoretical significance of life and living beings that focuses on Aristotle’s distinction between two ways of being developed in Metaphysics Book 9 – being potentially and being actively.