Bodily Substance
One basic concept of personal persistence over time is simply to have continuous bodily existence. However, as the Ship of Theseus problem illustrates, even for inanimate objects there are difficulties in determining whether one physical body at one time is the same thing as a physical body at another time. With humans, over time our bodies age and grow, losing and gaining matter, and over sufficient years will not consist of most of the matter they once consisted of. It is thus problematic to ground persistence of personal identity over time in the continuous existence of our bodies.
Nevertheless, this approach has its supporters. Eric Olson gives a definition of a human as a biological organism and asserts that a psychological relation is not necessary for personal continuity. Olson's personal identity lies in life-sustaining processes instead of bodily continuity. This biological approach squares with many other psychological accounts of personal identity but does not fall into common metaphysical traps.
Derek Parfit presents a thought experiment designed to bring out our intuitions about the corporeal continuity. This thought experiment discusses cases in which a person is teletransported from Earth to Mars. In the one case, the person enters the teletransporter and has each molecule of his body disassembled, teletransported to Mars, and then reassembled. In another case the person enters the teletransporter where that person’s body is destroyed while all the exact states of that person’s cells are recorded. This information is then teletransported to Mars, where another machine uses organic material to produce a perfect copy of that person’s body. The question is whether in either of these cases the person on Mars is identical to the person on Earth. Suppose that these two cases are just the furthest opposite points on a spectrum. In-between these two cases there are more cases in which an increase amount of the person on Mars is constituted of the numerically identical matter as the person on Earth. The question for that the criterion for personal identity becomes where on this spectrum does the person on Mars stop being identical to the person on Earth. Is it at 1, 51, or 99.9 percent? It appears that we are not able to draw a line. This inability appears to show that having a numerically identical physical body is not the criterion for personal identity.
Read more about this topic: Personal Identity, Theories, Continuity of Substance
Famous quotes containing the words bodily and/or substance:
“Sickness disgusts us with death, and we wish to get well, which is a way of wishing to live. But weakness and suffering, with manifold bodily woes, soon discourage the invalid from trying to regain ground: he tires of those respites which are but snares, of that faltering strength, those ardors cut short, and that perpetual lying in wait for the next attack.”
—Marguerite Yourcenar (1903–1987)
“All the old supports going, gone, this man reaches out a hand to steady himself on a ledge of rough brick that is warm in the sun: his hand feeds him messages of solidity, but his mind messages of destruction, for this breathing substance, made of earth, will be a dance of atoms, he knows it, his intelligence tells him so: there will soon be war, he is in the middle of war, where he stands will be a waste, mounds of rubble, and this solid earthy substance will be a film of dust on ruins.”
—Doris Lessing (b. 1919)