Introduction variations as each philosopher tries to


Many philosophers have been concerned with the identity of an object whose considerable part has been replaced gradually. Whereas some argue that the object retains its identity, others argue that the object loses the identity and it is no longer the same object. This paper will focus on the object identity and the three identity assumptions will be utilized in defining the identity of an object.

Theseus Paradox

The ship of Theseus has a philosophical issue or paradox which is generally referred to as the Theseus paradox. The main bone of contention lies in ascertaining whether an object whose all parts have been changed by way of replacement deserves to be identified as the same object. Many philosophers have tried to address the issue and take different stands.

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Some argue that the objects is still the same even after the replacement while others argue that the object is no longer fundamentally the same after the changes. The genesis of the question began when a ship (Theseus ship) had all the wooden parts changed and replaced by others (Benovsky, 2006). Some of the philosophers who have tried to address the paradox include Plato, Heraclitus, Socrates and the most popular is Plutarch. The Theseus paradox has many variations as each philosopher tries to address the issue and solve the problem.

According to Plutarch ((Blair, 2006)), the paradox originated from Greek legend “The ship wherein Theseus and the youth of Athens returned [from labyrinth in Crete] had thirty oars, and was preserved by the Athenians down even to the time of Demetrius Phalereus, for they took away the old planks as they decayed, putting in new and stronger timber in their place, insomuch that this ship became a standing example among the philosophers, for the logical question of things that grow; one side holding that the ship remained the same, and the other contending that it was not the same.” philosopher Plutarch puzzle lies in trying to answer the question; if all the ship’s part were replaced, would the ship remain fundamentally the same?

Plutarch was not alone in this as Thomas Hobbes followed suit and made the puzzle more complex by asking; if the original parts removed from the ship were taken and used in constructing another ship, of the two ships, which ship would be the Theseus ship.

Other philosophers include David Hume (Blair, 2006) whose philosophical perspective argues that “a ship, of which a considerable part has been changed by frequent reparations, is still considered as the same, nor does the difference of the materials hinder us from ascribing an identity to it. The common end in which the parts conspire is the same under all their variations, and affords an easy transition of the imagination from one situation of the body to another”.

From the propositions above, a prudent person would concur that by replacing few parts of an object or the ship in this case, the object retains its identity. However, if a considerable part is replaced, then it is difficult to give the object its original identity. Despite the various variations of the puzzle, some philosophers such as Wittgenstein do not argue that the puzzle is non-existent since it is a question of grammatical error (Blair, 2006).

Lowe’s Proposed Solution

Lowe came up with a solution that he intended would solve the identity puzzle in the case of Theseus ship. In order to understand his proposed solution, it is important to revisit the Theseus ship puzzle and make some assumptions. assuming that the rotting wooden planks (of ship A) were gradually replaced as each part became worn out, then the same planks were stored until all of ship A’s part had been completely replaced by new ones.

As such there would be a renovated ship which in this case will be called ship B. Replacement intuition assumption would claim that ship A is identical to be and the reverse is true. In addition, assume that the disposed parts of ship A were used to build another ship (C) identical to ship A. Applying the intuition of disassembly and reassembly, it follows that C is identical to A. This implies that C is identical to A, B is identical to A and therefore C and B are identical which is not true since B and C are not identical (Hurtig).

Lowe’s tried to solve the puzzle using two cases namely the ordinary case and the puzzle case. In the ordinary case, ship A’s part are gradually removed and stored without replacements and then, the stored parts are used to build ship C. In the puzzle case, the parts removed in a above are replaced gradually and the end result is ship B. the replaced parts are then assembled to form ship C.

In the ordinary case, Lowe proposes that it would be correct to ascertain existence of one ship whose parts have been fully complemented if half of ship A’s parts are with ship C in a warehouse. In the puzzle case, Lowes’s wonder what to say if ship A’s parts have been replaced by new ones to form ship B, at the same time, half of Ship A’s parts have been used to form Ship C (Hurtig).

In this case, the question of distinction arises since one ship has all its part together while the other one has half of its parts in the warehouse and others in the harbor. Lowe disagree with the proposition that two separate objects can share half of their parts on the basis that it falls prey to how we use our common sense when identifying objects (Hurtig).He adds that if all of ship B’s parts belong to ship and none of its part is with either ship C or ship A, then there is no single ship that has fully complemented parts.

From Lowe’s proposition, once some original parts an object are removed and placed in another distinct object, the parts ceases to exist as part of the object and even if they are put back together to form another object, the object becomes a new one distinct from the original one. In Hurting, Lowe’s proposed solution is summarized as follows “Either A is identical with B or A is identical with C. B and C are separate objects.

If there are two objects, x and y, there is no part z and no time , t, such that z is, a part of x at t, and a part of y at t. there is no time ,t, and no part , p, such that B and C share p at t . If A is identical to C, then there is a time, t, and a part, p, such that b and c shared p at t. A is not identical to C and A is identical to B” (Hurtig).

Possible Objections

Lowe’s proposed solution brings us to the conclusion that it is totally impossible for two distinct and separate objects to share parts and be viewed as one object. It is also clear that B is identical to A. However; Lowe’s proposed solution may not always hold water and this will be illustrated using an example.

Assuming that during the disassembly and reassembly process, A is identical to C and half the parts are in the warehouse while others are in the harbor. To certify that A and C are identical; either of the following two assumptions should be made. The first option would be to assume that a complete ship does not exist at the harbor during the middle stage of disassembly and reassembly.

In addition to that, the additional parts during renovation do not belong to any complete ship. The second option would be to say that some of B, s part is shared by ship C. The first option denies the fact that there is a ship with full complement of parts while the second one denies the fact the claim that it is impossible for two objects to share a considerable portion of parts. On such basis, Lowe’s proposed solution may face objections (Hurtig).


The ship of Theseus paradox is a complex situation that many philosophers have tried to unveil and they have come up with different solutions. Prior to giving my opinion on the case, it is important to list and discuss three assumptions that are associated with identity issues.

The first assumption is that of relation and can be viewed at in two different ways; identity as a transitive and symmetrical relation. A symmetrical relation proposes that if A is identical to B, the reverse is true. a transitive relation implies that if A is identical to B and B is identical to C, then C is identical to A and the reverse is true (Hurtig). The second assumption is that an object several joined parts can have some of its parts replaced gradually and still retain its identity.

The assumption is that if the parts are gradually replaced piece by piece, the object does not lose its identity. Finally, the last assumption assumes that an object that has been disassembled and reassembled does not lose its identity. If a person disassembles his personal computer with an intention of cleaning and then reassembles the computer again after cleaning, the computer is still the same.

However, in such a case, a question might arise regarding intermittent existence which in this case will be ignored (Burke, p.391). Based on the three assumptions, it is difficult to give a conclusive solution to the problem since some factors have to be ignored for any solution given. I would therefore conclude that an object does not lose its identity if some of its parts are gradually replaced piece by piece. However the number of parts replaced should minimal, otherwise the object loses its identity.

Importance of Object Identity

An object has both numerical and qualitative identity. For anybody to answer the question whether an objects identity over time is of any importance, it is important to distinguish between numerical and qualitative identity. Numerical identical means that the objects are the same.

For example, if there are two mobile phones from the same company and went through the same processes, then the phones are just one phone but not two. Qualitative identity is associated with similarity, i.e. the two phones are not one but two different ones (Zalta, 2010). As such, importance of identity of objects overtime depends with the situation.


Benovsky, Jiri. Persistence through Time, And Across Possible Worlds, Heusenstamm Hessen, Germany: Ontos Verlag, 2006.

Blair, David. Wittgenstein, Language and Information: ‘Back To the Rough Ground!’ N.Y, Springer, 2006

Burke, Michael. Cohabitation, Stuff and Intermittent Existence. Web.28 Feb.2012

Hurtig. But it’s My Ship. Web.28 Feb.2012

Zalta, Edward (e d).”Personal Identity“, the Stanford Encyclopedia of Philosophy, 2010. Web.28 Feb.2012.>