Online research in philosophy

According to the psychological account of personal identity for someone to be one and the same person over time Y today must have some of the beliefs, desires, intentions and memories that X had yesterday, as well as some memories of the events that happened to X yesterday. But, on this account, we have the undesirable result that persons can be reduplicated unless we add an additional requirement: Y is uniquely psychologically continuous with X. In an attempt to avoid the problem of reduplication in a different way I invoke arguments for active externalism and the embodied mind. The motivation for exploring embedded and embodied approaches to cognition is that they cast doubt on the easy separation of brain and body which is often taken for granted in the identity literature. With these approaches in mind, the simple assumptions by which brains are imagined to be transplanted into new bodies, and agents are said to be teletransported to new environments should be reviewed. Whilst embodiment provides us with some reasons to re-evaluate our understanding of brain transplant thought experiments, we ultimately see that the nature of teletransportation is consistent with the mind as both extended and embodied.

Many have claimed that split-brain patients are actually two persons. I maintain that both the traditional separation argument and the more recent sophistication argument for the two persons interpretation are inadequate on conceptual grounds. An autonomy argument is inadequate on empirical grounds. Overall, theoretical and practical consequences weigh heavily in favor of adopting a one person interpretation.

This paper challenges the widely held theory that split-brain patients have ‘two-minds’ and can thus be described as being two distinct persons. A distinction is made between the singularity of mind and the coherence of mind. It is stressed that ‘a single mind’ is not something posited to explain coherence among mental contents, but is merely a mark that such coherence holds to a certain degree. However, there is no sharp dividing line regarding what counts as a single mind. It is argued that mental coherence is always a matter of degree, and that our concept of a single mind can accomodate spit-brain phenomena.

In "Consciousness Explained," Dennett (1991) denies that split-brain humans have double consciousness: he describes the experiments as "anecdotal." In attempting to replace the Cartesian Theatre of the Mind" with his own "Multiple Drafts" view of consciousness, Dennett rejects the notion of the mind as a countable thing in favour of its being a mere "abstraction." His criticisms of the standard interpretation of the split-brain data are analyzed here and each is found to be open to objections. There exist people who have survived left ["dominant"] cerebral hemispherectomy; by Dennett's criteria, they would not have minds.

This paper concerns the relationships between persons, brains, behaviour, and psychological explanation. Tye defines a ‘psychological framework’ (PF) as a set of token beliefs, desires, intentions, memories, streams of consciousness, higher-order mental states, etc., that ‘form a coherent whole’ and against which a creature’s ‘behavior can be explained’ (p. 141). A person is the subject of such a psychological framework. Each person has one PF, and with each new PF there is a new person. Meanwhile materialism tells us, according to Tye, that brains are the bearers of mental states. In other words, ‘each person is a brain’ (p. 142) — or rather a ‘global physical state of the brain,’ since Tye believes that a single brain might realize multiple PFs and thus constitute multiple persons. Most of this paper simply assumes Tye’s account of personal identity, in order to expose certain contradictions within what Tye says about personhood in split-brain subjects. Towards the end of the paper, however, I turn to alternative accounts of persons. While a method of individuating persons grounded in scientific psychology would identify persons with psychological frameworks, as Tye does, perhaps an account of personhood grounded either in a non-psychological science, or in non-scientific psychology, would better fit the interests we have in personal identity.