THE SHIP OF THESEUS: SOME DIFFERENT CASES

1. The parts of the ship are gradually replaced so that eventually all of the old parts are gone, with the parts that are removed being destroyed. Two subcases:

a. The removed parts were rotting and needed to be replaced.

b. The removed parts were sound.

2. The ship is dismantled, the parts are stored in a warehouse, and then after some elapse of time a ship is reconstructed from the stored parts.

3. Combination of 1b and 2: the parts of the ship are gradually replaced with new ones (resulting in the renovated ship), the old parts are stored, and eventually the stored parts are reassembled so as to produce a second ship (the reconstructed ship).

4. We start with two qualitatively identical ships, A and B. Their parts are then gradually exchanged, so that eventually in the original location of ship A there is a ship made up entirely of the original parts of ship B, and vice versa.

5. Like case 4, except that after the parts of ship A have been transferred to ship B, they are replaced with new parts, stored, and eventually reassembled into a third ship. Two subcases:

a. The parts of A were all together at one time after being transferred.

b. Some of the transferred parts of A were replaced in B before all had been transferred, so that they were never together at one time (after leaving A).

6. The parts of the original ship are gradually disbursed as replacements for parts in many other ships, until eventually none are left in the original location. After a time, they are retrieved and reassembled into one ship. Two subcases:

a. The removed parts are replaced in the original ship with new parts.

b. The removed parts are not replaced, so that the original ship gradually disappears.

7. Like case 3, except that the original parts are continually reassembled in a different location, rather than being stored.

8. The original ship is disassembled and stored. Later two ships are assembled, each using half of the old parts plus new parts.