Personal identity and Parkinson's

When faced with a diagnosis of a chronic, incurable disease such as Parkinson’s it is tempting to think you have lost your identity and become a disease. Is this valid? Do I become a different person as my symptoms get worse?

Since the onset of Parkinson’s I have become qualitatively different to the symptom-free person I was in the past (indeed, we are all different compared to the people we were in the past). However, I still describe that past person as me because of the numerical sameness he shares with me; there has only been one of me in the past and now in the present. In other words, my personal identity has remained non-branched and continuous despite, for example, growing into an adult.

My numerical sameness can be described as either “spatiotemporally continuous” or “psychologically continuous”. Spatiotemporal continuity means during my life I have carried out a single, continuous series of actions in space and time that can be traced back to my conception. Psychological continuity states I have the same identity as my past self because I share memories and character traits etc with him.

This raises a question: how much continuity is needed to maintain my identity? Spatiotemporally I can lose significant parts of my body and still be myself but if all the atoms that make up my body were separated I would cease to be me. Psychologically, I can gain new memories and experience new mental states (e.g. depression) but I can still identify with my past self and maintain my identity. There is significant flexibility within personal identity to remain who you are.

Therefore, Parkinson’s may restrict my body and affect my emotions but it won’t be sufficient to change who I am.

This essay was inspired by “Riddles of Existence” by Earl Conee and Theodore Sider.

dr jonny
dr jonny --

I enjoyed your essay very much. My own viewpoint during my 15 years of PD has been that this disease alters me only as other external forces and circumstances also alter me in behavior or emotion. That is, as I age, the changes in my daily living, such as my move from California to Oregon and the births of my grandchildren, affect who I am. I have an entirely new role or new compartment in my life now that I have become a grandmother. Moving to an adjacent state sounds like nothing, but the way of life in Silicon Valley (crowded, hectic, and competitive) and the way of life in the nature-oriented Northwest are drastically different. The change has led me to spend my free time in new ways and to relax more. I consider these and other alterations to be mere modifications that occur naturally during the course of a lifetime.

But when I was first diagnosed, I remember that one of my fears was that I would be defined by this disease in the eyes of others. My self-assessment was not in question (probably an indication of a big ego), yet I worried that other people, learning that I have PD, would see me as a patient rather than as a person. If my right hand trembled and I saw someone's eyes travel to that hand, I felt unwarranted resentment. If my husband looked at me for too many seconds, I was sure he was trying to observe symptoms. This period of defensive resentment did not last long, fortunately. After a few months I found myself offering an explanation to anyone who noticed a tremor or an awkward movement; I began to feel more casual about my condition and other people's views. The only time a little inkling of resentment still emerges is in the case of unsolicited assistance; I have had to teach certain friends that my being slow at some tasks is not automatically an appeal for help, that I can do what I have always done if given the freedom to act alone.

Thus, I feel that my life has been a continuous experience, unbroken by and rather enhanced by diagnoses, deaths, births, and my circumstances of daily living. The entity that is me just keeps changing shape, altering its characteristics, but never losing its recognizable identity.