Personal Identity, Direction of Change, and Neuroethics

The personal identity relation is of great interest to philosophers, who often consider fictional scenarios to test what features seem to make persons persist through time. But often real examples of neuroscientific interest also provide important tests of personal identity. One such example is the case of Phineas Gage – or at least the story often told about Phineas Gage. Many cite Gage’s story as example of severed personal identity; Phineas underwent such a tremendous change that Gage “survived as a different man.” I discuss a recent empirical finding about judgments about this hypothetical. It is not just the magnitude of the change that affects identity judgment; it is also the negative direction of the change. I present an experiment suggesting that direction of change also affects neuroethical judgments. I conclude we should consider carefully the way in which improvements and deteriorations affect attributions of personal identity. This is particularly important since a number of the most crucial neuroethical decisions involve varieties of cognitive enhancements or deteriorations.