Quixotic Evil

A computer is really the sum of it's components. As you have changed most of the major components it could be argued it is a new machine - in an old case.

Microsoft are a pain in the butt when it comes to licensing. :) I have vague memories of reading somewhere on their site that if you change more than x percentage of parts on your machine you will have to re-activate the software and this might necessitate phoning them up and persuading some flunky that it is still the same machine. This may have changed, it's been a long time since I have bothered reading anything on their site.

In response to the other philosophical question, if they also replaced internal structural components as they went along it can no longer be considered the same ship.

I have at times had to ring the flunky, but he seemed to just take my word that it was the same machine. I think that was probably the time I changed the processor, but it could easily have been based on a percentage, as you say.

I can't agree with the ease with which you solve the philosophical question though ;-)
The reason questions like that have interested philosophers for centuries is because they can't be answered with any certainty.

Take a new ship, note a time index T0 and call the ship S0. Change half the constituents, and call it S1 at T1. Change the other half and at T2 define S2.
If your criterion is that ships are the same if they have any components in common, then S0 and S1 are the same ship, as are S1 and S2, yet S0 is not the same as S2.
I for one wouldn't be happy with then identity function that doesn't commute. Its behaviour is too unpredictable.

But that's the beauty of the problem...

Back again.

I accept all you say but would put the question differently.

Can the ship be described as original? If no then how do you describe it? Can the ship be described as new? If not then what description do you give it?

The real question should be at what point should you determine that gradual change has altered the the definition of the object and does it require an intermediate description?

I used to be a furniture restorer to trade and this question bears relation to acceptable levels of repair on period pieces and how they should be described. It always creates arguments in the trade but in general once more than 40% of the main structural components are replaced it moves into a different classification. Insofar as minor repair is acceptable on a period item, major restoration affects value.

My personal opinion is - Once you replace any one major component the item is not original and therefore not the same even if that was done within the same time period of the item. But it does not make it a new item it just makes it an altered one. If it has been altered it's not the same.

That does open up all sort of questions pertaining to definition of major component etc so it probably doesn't help. But then I never said I was logical. :)

I think Microsoft worked on the basis of change of major components and/or cummulative changes of more than 3 lesser one's. Still haven't looked it up though. Wonder what their philosophy would be in relation to this question....:)

I'm intrigued by the fact that the furniture restoration trade argues about it. Is the 40% an industry consensus or was it imposed by a governing body or legislation?

It's nice to find real-world problems similar to philosophical ones, if only to see how different the answers can be. While students of metaphysics may be happy enough to approach the issue from a 'wouldn't it be nice if there was some perfect way of telling', the furniture restoration trade presumably needs to know 'what is fair description for the customer' and Microsoft is likely thinking 'what can our lawyers enforce'.
The range of answers to essentially the same question is always interesting.

There's nothing wrong with giving an answer that raises new questions, provided you are prepared to try and answer <i>them</i> too ;-)

Thanks for your comments, and especially for coming back after the one that could have been read as dismissive and/or antagonistic. Always nice to be read...

The 40% is a consensus of opinion and even then will vary considerably I should probably have given a range 40-60% and that's just in the UK. There is no legislation on this issue and various Trade Organisations tend to be vague, arbitrary or just confusing in their definitions. Put x no of dealers and/or restorers in a room and you will get x no of opinions. Mine reflects the unwritten consensus of those with whom I did business, it's a necessary part of the trust process which at one time governed the antiques trade but sadly doesn't exist so much now.

To be honest the Antiques trade (possibly being overly generalist here) has never worried too much about philosophical or ethical questions unless there was a risk of being caught out. Good restorers have always pondered these before putting them away and getting down to business. :) One has to eat.

I habitually proffer opinions rather than logical arguments/statements but am always happy to be challenged and attempt to justify my reasoning. So i'm not offended.

After my last comment I couldn't get to sleep, one of the reasons I rarely consider philosophical questions.I'm still left pondering how you define the issues of originality and change if bringing them into the question you put.

From the moment the shipbuilder said "finished" that ship has entered into a process of change. The trundle down the rollers into the water will cause shifting, settling and stress. The water will cause the wood to swell and change in density and structure. Salt water will also cause chemical reactions between any metal and the acids in the wood wherever they come in contact. The list goes on. A good shiplbuilder will have allowed for these in the construction and produce something that may last with care, a bad shipbuilder won't and the ship will disintegrate quicker. These are all issues a restorer should consider when working on an item of this nature.

From a philosophical viewpoint how do you address this? Is anything original for more than a brief moment? Does it matter? At what point in time can you say this process of change has reached a point where the item is different?

When I am restoring something I don't try to take it back to it's original state, I try to take it to the point it should be at this moment in it's life. Since there is no formula for defining that I have to go by instinct. A difficult judgement call.

A piece of period furniture still around today bears little relation to the way it looked when it was first made. Much of it's appeal actually comes from the ageing process and years of use/misuse. It may be genuine but is it the same item? My feeling is that it has gone through some process of metamorphosis into something different to the original makers intention and is something new. That's another impossible conundrum. How do you prove,measure or define it?

My argument would be that S0 and S1 are different and S1 and S2 are also different therefore S0 and S2 are different. That commutes but it also relies on an arbitrary decision as to point of change that cannot be proved logically. Which brings me back to How do we define change?

Since I'm just going round in circles I'll go now. :)