lesser philosophers have asked, "what does it mean for something to be 'original'? if this knife, passed down from the time of my forefathers, occasionally has this bit or that bit replaced, until the whole thing is an assemblage of patches and amendments, is it the same knife? if an ancient building is from time to time renovated and perhaps even rebuilt, is it the same building, standing in the same spot for centuries, or did it gradually become a new construction somewhere along the way? what is identity, metaphysically, of an object--or a person, or an abstract group of people?"
to this i say, the answer is in fact obvious, and this air of mysticism totally unnecessary: identity is a diaphanous, strongly self-adhesive, self-replicating, psychically active fluid which inheres in objects when someone takes pride in their creation, and which dissipates when separated from the bulk of its mass.
we know identity is diaphanous, because it is is not physically perceptible, at least by modern scientific instruments. i have faith that one day our particle accelerators will discover the fundamental unit of identity, perhaps some sort of onton or essino.
we know identity is strongly self-adhesive because placing two objects in close proximity to one another permits identity to flow between them only very slowly, if at all. identities do not readily mix, perhaps due to small-scale properties analogous to the chemistry of ordinary matter. nonetheless, identity is not completely insoluble, as anyone who has discovered their own identity is bound up in that of a larger group or movement can attest.
it self-replicates, growing perhaps in some crystalline fashion, because when an object of one identity has a part dissevered, and another attached in its place, that part eventually becomes an element of the whole. this part need not even replace an original one: antique frames become as much a part of the painting they hold as the pigments and canvas. when you replace the deck-planks of theseus's ship, they become part of the Ship of Theseus when there has been enough time for identity to flow into and fill them.
and how do we know this? because identity is psychically active. our minds naturally react to its presence, probably because they are themselves such rich reservoirs of identity, and we have evolved through natural selection to skillfully navigate the ontoecological environment we find ourselves embedded in, and indeed create. while identity is a natural phenomenon to a certain extent, it is generally present only in small amounts absent the prodigious psychic effect of the human brain, which produces the vast majority of identity found on earth today.
this is fortunate, as it allows us to use our experience of identity as a way of measuring it and understanding its properties. we can thus adduce additional interesting properties. one, that identity inheres in an object in the moment of its creation or shortly after, in proportion to the emotional weight put on the act of creation. thus, an artist or craftsman working alone to produce a masterpiece creates an object with a great deal of identity, which is psychically very potent. mass-produced industrial products, which have barely any active involvement of any sapient being in their creation, are comparatively psychically inert, and thus of little value.
humans, of course, continually invent and re-invent themselves, and so have the most identity of any known object in nature. moreover, they can store so much identity that they may be part of many objects at once: localities, nation-states, sports fandoms, etc., a type of persistent but manifold identity otherwise found only among the largest physical objects like geography.
for my research program into the physical fundamentals of identity, and my search for the onton, i propose a series of experiments that involve high-energy collisions between various kinds of conceptually complex identity: priceless works of art that have undergone extensive restoration, very old architectural landmarks that have several distinct phases of reconstruction, politically active sports fans (and, naturally, their opposite numbers supporting opposing movements/teams), etc. unfortunately the philistines at CERN and UNESCO are not currently returning my calls. so you see, officer, i am in fact a respected and distinguished scientist. i am not, as you so rashly claim, "robbing this art museum." the political activists bound and gagged in my trunk are my research assistants. nothing untoward is going on here. i am simply investigating the nature of truth.