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Personal Identity Notes
Qualitative Identity
Being exactly similar in qualities (e.g. Tweedle-dum and Tweedle-dee)
Numerical Identity
Being exactly the same person, but with different qualities (e.g. Dr Jekyll and Mr. Hyde)
Necessary Conditions
A condition which it is required to have in order to be something. (e.g. it is necessary to be warm-blooded to be a horse) but having that condition (being warm-blooded) is not the only quality needed (to be a horse. It is possible to be warm-blooded and not be a horse.)
Sufficient Conditions
Conditions can be sufficient but not necessary. It fulfils the criteria of being British if you are born in Britain; however, there are other conditions which would make someone equally British (e.g. marriage).
Continuity of Soul
- The body plays no part in a person’s identity – if two people were to swap bodies, they would be the same person but in a different body.
- The numerical identity is not necessary or sufficient for personal identity.
- Continuity of soul is consistent with Cartesian ideas, with notions of reincarnation and experiences of the self remaining despite physical changes to the body.
Continuity of Body
- The body traces a continuous track through space and time.
- The body may still change, changes can still occur within the same structure and the person have the same identity. Spatio-temporal continuity is required.
- Bernard Williams - Guy Fawkes example: two brothers, Charles and Robert both claim to be guy Fawkes. They make memory claims closely fitting in with Guy Fawkes’ life and the same personality – which one is Guy Fawkes? The answer is neither if neither of them have bodily continuity with him – as Charles and Robert were born, they cannot be Guy Fawkes.
Continuity of Brain
- The brain contains the information (memories, experiences, personality etc.) A person’s body is neither necessary nor sufficient for the identity of a person, so long as the brain still exists.
- Sydney Shoemaker – Robinson & Brown example: Brown’s brain is put into Robinson; the combination of them is called Brownson. Brownson has Brown’s traits and memories etc. So Brownson is Brown despite having Robinson’s numerically different body.
- Wiggins and Parfit – Florence example: Florence’s brain is divided into two hemispheres and each is placed into an empty skull. The two Florences have full memories and refer to themselves in the first person as Florence – so which one is Florence? Possible answer: ‘personal survival without identity’ i.e. Florence survives, but is not numerically identical with either Florence.
Continuity of Psychology
- Personal identity depends on the ability to link past, present and future consciousness and awareness.
- “It is by the consciousness it has of its present actions that it is self to itself now, and so will be the same self as far as the same consciousness can extend to actions past or to come” – Locke. Locke states if an individual has consistent consciousness that they were, are and will continue to be themselves then they can be said to have personal identity.
- Thomas Reid – Soldier example: A boy was flogged for stealing apples, he then grew up to be a brave ensign and then a general. The ensign remembers stealing apples and so is the same as the boy. The general remembers being a brave ensign and so they are the same. The general cannot remember being flogged and so is not the same as the person who got flogged. By using consciousness as a criterion on personal ID, there is a contradiction as the general both is and is not the boy.
- Parfit’s revision of Locke – Continuity and connectedness as a looser criterion. As long as there is continuity and connectedness to a person’s consciousness they can be said to be the same. E.g. as the ensign remembers being the boy and the general remembers the ensign, the general must have been the boy as well. People with severe amnesia would therefore not be the same person, as there is not connectedness of past memories to present.
- Butler’s Objection to Locke – Butler claims Locke’s argument is circular. “Consciousness of personal ID presupposes and therefore cannot constitute personal identity”. As you must be conscious to have an ID. In stating that consciousness is necessary presupposes there is someone to be conscious. You can’t use consciousness to explain personal ID, because consciousness depends on personal ID. Parfit’s response is that a person can be described in impersonal terms e.g. a combination of experiences, thoughts and actions.
Brain State Transfer Machine
A machine can copy you exactly – thoughts, experiences, molecules etc. It destroys your body and rebuilds it exactly in another place, acting as a transporter. There is no bodily continuity, but strong psychological continuity. Parfit thinks that the duplicate is you, just that the machine rather than your brain preserves your psychology temporarily.
Unger’s response – physical continuity is necessary for the preservation of personal identity, as the psychology is stored in the brain. When the brain is vaporised, it ceases to exist and a new one is created and so there is no physical, and so no psychological continuity so personal ID does not survive.
Comment
These notes are aimed at people studying for AQA A2 Philosophy Personal Identity.
Origianlly written by Sopheh on TSR Forums.
