Angus and Freddie cycled along Salamander Street, which turned into Baltic Street, which turned into Bernard Street. They were in Leith looking for Victoria Dock, where a square-rigged sailing ship was supposed to be tied up.

            Suddenly Angus caught sight of something that looked like the mast of a sailing ship.

            That's it!' he shouted to Freddie.

            'You're right,' Freddie shouted back, excitedly; 'but how do we get to it?'

            The tip of the mast could be seen over a large warehouse that stood behind a high fence. The boys couldn't find a way in.

            'Oh, look,' said Freddie suddenly, pointing to an open gate; 'I think we can get to the dock through there.'

            The boys cycled through the gate and along a deserted road until, all of a sudden, there was the tall ship, tied up in a small harbor next to a double-decker bus. When they got closer to the bus, they saw it served as a ticket office, where they could buy tickets to board the ship and look around.

            The ship, 'Maria Magdalena' was her name, had been sailing around the British Isles. At each port the crew welcomed visitors aboard, so long as the visitors bought tickets in the double-decker bus. When the ship set sail for the next port, the bus followed along by land, met her when she arrived in port, and sold more tickets to more visitors.

            Freddie and Angus bought their tickets and then spent the afternoon happily looking around the Maria Magdalena.

At the dinner table that evening Freddie was asked to tell his family what he and Angus had seen in Leith Harbor. He was still very excited, but not too excited to tell them about the tall masts, the endless rigging, the cozy cabins, the small bunks where the crew slept and, of course, the double-decker bus, where you buy tickets to board the ship.

            'It's a very beautiful ship,' Freddie explained; 'it's all gleaming white. It's like a ship in a movie. In fact, it has been used in making pirate films.'

            'Did you say how old the ship is?' asked Freddie's father.

            'I think the guide said it was built about 1840, or something,' replied Freddie; 'but only a few years later it got sunk, in a big battle. It stayed on the ocean bottom for years and years. Then, about two years ago, it was salvaged, brought up from the bottom. It's now the oldest sailing ship afloat.'

            'Really!' put in Freddie's mother; 'then it must be quite dilapidated.'

            'Oh, no!' Freddie assured her; 'not at all. The guide told us that when they brought it up... uh, brought her up.' Freddie suddenly remembered that ships are considered feminine -- they found that much of the decking was rotten. So they replaced most of that, board by board. Then they found that some of the ribs were rotten, too; so they replaced them. Finally, they got worried about the sides, you know, the outside of the hull. They ended up replacing much of that as well, one board at a time. Now almost all the boards on the ship are new, and very smooth, and solid, and well painted. She's a beautiful ship.'

            'Then it can't be the oldest sailing ship afloat,' sneered Alice, ignoring the rule about calling ships 'her'; 'it can't be, if almost all the boards are new. It's a new ship. It may be modeled after an old ship, but it's a new ship.'

            Freddie was stunned. He had been imagining the battles the Maria Magdalena had fought. He had been wondering what the sailors who had sailed her were like and what it would have been like to be a cabin boy on the ship when she had set sail for the Far East. He had been so proud to be standing on the deck of a ship that had sailed so long ago.

            Now it seemed to Freddie that Alice was right. The ship he and Angus had boarded in Leith Harbor, the ship the guide had said was the oldest sailing ship afloat, wasn't really; she was only a copy of the Maria Magdalena. No, she wasn't exactly a copy either. She was something the Maria Magdalena had . . . sort of  .  .  .  turned into  .  .  .  a new ship the old ship had turned into.

            But the guide had said she was the oldest square-rigger afloat. Freddie was sure of that. Was the guide wrong then?

*     *     *

            This is another story beginning I wrote for my philosophy class in St. Mary's Music School in Edinburgh, Scotland, in 1982. The story is based partly on a real experience my wife, my son, John, and I had shortly after we arrived in Edinburgh. We had read about the old sailing ship tied up in Leith Harbor, which is the port for Edinburgh. We decided to go visit her.

            As my family and I were being escorted around the ship, the guide dropped the remark that, although she was the oldest sailing ship afloat, in fact roughly 97% of her timbers had been replaced. My wife and son could hardly believe their ears. They had heard me tell the old philosophical story of the fabled Ship of Theseus, whose boards had been replaced, one plank at a time, until all her boards were new.

My wife and son, as well as my two daughters, who were then in college, had puzzled with me over the Ship of Theseus. Had she survived the piece-by-piece replacement of all her boards? Or was the result that she had been displaced by a new ship, exactly the size and shape of the old one? If the original ship had ceased to exist and been replaced  a new ship, when did the old ship cease to exist and the new one come into being? When the last plank was replaced? Or when one more than half the boards was replaced? Or at some other time?

            There are, of course, philosophically interesting variations on the traditional story of the Ship of Theseus. In one version there are two ships, exactly alike, in adjoining docks. Someone begins exchanging planks, until finally the ship in Dock A is made up entirely of planks from the ship that was originally in Dock B, and vice versa. At the end of the piece-by-piece transfer presumably the ship originally in Dock A is now in Dock B, and vice versa. But, if so, at what point did the transfer take place?

            Another version has the boards that are taken off the Ship of Theseus, and replaced one at a time, stored in a warehouse. When, finally, all the old boards have been replaced, they are taken out of the warehouse and reassembled. Now which is the Ship of Theseus -- the ship that has resulted from piece-by-piece replacement, or the one that has been put together by assembling all the old planks that had been stored in the warehouse.

            If you discuss 'The Ship' with a group of kids, you can expect someone to point out that the cells of our bodies, or at least most of them, also get replaced, one at a time. The analogy between an artifact, such as a ship, and a living organism, such as a human being, is certainly worth exploring.

            If you want to see what happened when I discussed 'The Ship' with the kids in my class in Edinburgh, check out the chapter, 'The Ship,' on pages 37-48 of Gareth B. Matthews, Dialogues with Children (Harvard University Press, 1984).

            If you and the kids you discuss this story with come up with an ending to 'The Ship' you want to share with me, please send it to me, either by e-mail to matthews@philos.umass.edu, or by U.S. or international mail to Gareth B. Matthews, Philosophy Department, UMass, Amherst, MA 01003-9269.