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Selfhood and ethics: Who am I and why does it matter?

by Keenan Davis

The following post is part of a special series emerging from Contemporary Issues in Neuroethics, a graduate-level course out of Emory University’s Center for Ethics. Keenan is a graduate student in Bioethics, whose work focuses on the use of virtue ethics and natural law to evaluate novel biotechnologies. He will be pursuing a PhD in the Graduate Division of Religion in the fall.

What should I be doing with my life? Many approach this timeless question by considering first another: Who am I? For a wide range thinkers from Plato to Dr. Phil, we can only know what to do with ourselves when we truly know ourselves. Who we are determines and constrains how we ought to behave. For example, because my parents caused me to exist, I should behave towards them with a level of gratitude and love. Perhaps through a cause-and-effect dynamic, as a result of being their son, I should treat them respectfully. We will return to this example at the conclusion of our exploration.

Historically, the question of selfhood was assessed in terms of an afterlife, seeking to resolve what happens to us when we die. If, as Plato claimed, a person is nothing more than his soul, “a thing immortal,” then he will survive physical death. Indeed, perhaps one should look forward to the separation of the soul from material constraints. How we ought to behave then is for the sake of existence after and beyond this world, a position shared by many adherents to Abrahamic religion. On the other hand, if we are no more than our bodies, then we do not persist after death and have no reason to orient our behavior toward post-mortem expectations. Such is the position of Lucretius and the Epicureans who conclude that our practical task is instead to flourish within a strictly material context. Our behavior should be for the sake of this world. For both Lucretius and Plato, the metaphysical substance of self is what mattered foremost.

John Locke

As part of the 17th century Enlightenment, John Locke changed the focus from the substance of self and more explicitly addressed the issue of selfhood with an eye to its normative consequences. For instance, he believed the self to be based entirely on memory and consciousness, regardless of the relationship between body and soul. By defining personhood as continuous self-identification through memory, Locke aimed to establish psychological criteria for moral agency and responsibility. Only if one is responsible for particular actions ought he be liable for judgment, reward, or punishment. Despite his emphasis on the psychological, as opposed to the biological or spiritual, Locke’s definition of self still follows the cause-and-effect pattern of is then ought: who I am determines how I should behave.

Using thought experiments like the famous Ship of Theseus conundrum, philosopher Trenton Merricks of the University of Virginia undermines this line of thought by suggesting that there is no metaphysical answer to the question of who we are. There simply are no necessary and sufficient criteria—psychological, bodily, or otherwise—of identity over time for any object. Lest we take this conclusion too far, Merricks explains that it does not mean that persons and objects lack essential properties or evade description: “Among my essential properties are, I think, being a person and failing to be a cat or hatbox.” His assessment just means that not all explanations or identifications involving characteristics need to be stated in terms of absolute proof. Allowing a modest concession to unavoidable skepticism, we need not (nor do we ever) demonstrate infallibly that “the tree in my yard today is the same tree that was in my yard yesterday” to warrant that belief. We can still be warranted in our beliefs regarding who we are without proving them absolutely certain.

Merricks demonstrates that a strict criterialist account of the self is insufficient alone: we cannot point to a single necessary and sufficient criterion of self that might help us figure out what to do with ourselves. Perhaps then we should consider an emergent understanding of self, in which the many aspects of our selves coalesce to a self that is greater than the sum of its parts. Plato, Lucretius, and Locke all seemed to be somewhat right in their descriptions of who we are: our minds, bodies, and souls all at least contribute to our sense of self, even if no one of them defines it entirely.

This is the starting premise of psychologist Nina Strohminger and philosopher Shaun Nichols, who sought to determine if there exists a perceived hierarchy of these components. Their paper “The Essential Moral Self” reveals which aspects of our identity contribute most to our narrative of self. Their experiments involved surveys asking people to consider the fate of someone who suffers brain trauma, takes a psychoactive drug, moves from one body to another, is reincarnated after death, or undergoes age-related cognitive changes. From these surveys, distinct patterns emerged illuminating how personal identity is actually defined by most people.


Strohminger and Nichols found that “folk intuitions largely accord with the psychological view” endorsed by Locke but note that specific aspects of the psychological criteria are much more highly valued than others, “challenging a straightforward view of psychological continuity” as the definition of selfhood. Indeed, even various bodily traits are ranked above many psychological traits. Across the five experiments, though, they found “strong and unequivocal support” for their “essential moral self hypothesis,” which states that the subset of psychological traits they refer to as moral traits (e.g. kindness, empathy, goodness) are considered more important than any other in defining personal identity. For instance, in the survey asking participants which traits would follow a person through a body-swap, the traits most highly ranked were honesty, goodness/evilness, and conscientiousness. The category of moral traits as a whole was prioritized significantly higher than other categories, including perceptual traits, somatic traits, and even memory. These studies demonstrate quite plainly that our morality is central to what it means to be oneself and to know who we are.

Rather than basing how we should behave on the metaphysics of who we are, this study indicates that the reverse is true. Our ethical orientation appears to be the primary constituent of our selfhood! The relationship between who we are and how we ought to behave seems to be more complex than a direct cause and effect. It is instead more like an irresolvable dialectic. Our selfhood is in large part constituted by our ethics, which is informed and directed in turn. Returning to our opening example, perhaps my status as a son is only truly and deeply established by the extent to which I fulfill my obligations to my parents, by how respectfully I treat them. The “essential moral self hypothesis” of Strohminger and Nichols merits greater exploration and will certainly have much to contribute to understanding this complex dynamic. Clarity regarding this dynamic will go far moving forward to ethically evaluate biotechnologies that potentially threaten our authentic selves, such as cognitive enhancers and moral enhancers in particular.


John Locke, An Essay Concerning Human Understanding (1694), Book II, Chapter XXVII, pp.33-52

Trenton Merricks, There Are No Criteria of Identity Over Time, Noûs 32 (1998): 106-124

Nina Strohminger, Shaun Nichols, The Essential Moral Self, Cognition, 131 (2014): 159-171

Want to cite this post?

Davis, K. (2015). Selfhood and ethics: Who am I and why does it matter? The Neuroethics Blog. Retrieved on , from


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