Immutability and Change
Is change real? The question is of pre-Socratic antiquity and I probably have nothing new to say about it. Still, the truth is sufficiently strange to be worth reiterating: change is surprisingly absent from the world, more a matter of appearance than reality. Two things don’t change: particles and properties. The same elementary particles pass from object to object over eons of time—eternal, immutable, imperishable. The very same electrons that populated the early universe are still here, pinging around, oblivious to the passage of time (to them time has no meaning). Particles are permanent. Similarly, properties don’t change, just as Plato said: particulars come and go, subject to change, but universals are forever. When an object changes color, say, the property itself doesn’t change so that the property that was once green is now yellow; rather, green is replaced by yellow. We don’t have green still instantiated but now turned yellow—green can’t be yellow. Universals don’t change their nature over time: they don’t persist through (qualitative) change. They stay the same; they are immutable. True, they may cease to be instantiated at a given time, so that different things become true of them, but they suffer no internal alteration. Do they persist when not exemplified? The question is difficult, but it is not clear that they don’t—a Platonist says yes, an Aristotelean no. If they don’t, we have to say the universal is recreated at a later time, which raises the question of whether it is really the same thing, given the lack of continuity through time. Also, it may be that our conception of universals fails to capture their inner nature: maybe they exist between instantiations in some form that we don’t (or can’t) conceive. In any case, the thing itself doesn’t change: it is the same in different objects at a given time and it is the same when it crops up at different times. Universals are like diamonds (only harder): they eternally retain their integrity, their ontological resilience, their imperishable quiddity. Plato was right: universals, unlike (non-elementary) particulars, are immutable, indifferent to time. So, the particles that compose an object (a changeable particular) don’t change, and neither do the properties that the object instantiates. But isn’t that all an object is? Isn’t an object a combination of substance and form—so what allows it to change? The elementary parts don’t change and neither do the properties, so what is left to change? The answer is that the particles get rearranged and different properties come thereby to be instantiated—as when an animal is created and grows. Change of place for the particles translates into qualitative change for the particular; it changes, not its constituents and properties. The reason is that objects persist through motion of their parts (their arrival and departure). They are identical under variation of their parts (and properties). The aggregate of parts gets replaced but the particular soldiers on. If that were not so, nothing would change. We would just have a new object instantiating new properties, not an old object persisting under change. It is only when the world is viewed through the lens of sortal concepts that change becomes visible; change is unreal at the level of basic ontology. It doesn’t happen to the simple objects that compose more complex objects, and it doesn’t happen to the universals that give objects their nature—these remain unaltered and permanent. It happens to rocks and raccoons and real estate, but not to what makes these things the things they are. I therefore see no alternative to saying that reality is basically changeless: not just universals, as Plato contended, and not just atoms, as Democritus held (and modern physicists), but the whole caboodle. Change is superficial not deep. We think change is deep because our senses report change—things look to change shape and color—and because we ourselves are constantly changing; but actually, the building blocks of reality are impervious to change. It is the belief in identity through time (true or false) that convinces us of the reality of change; without that we would experience the world as a succession of new objects (aggregates of particles) exemplifying new properties. Things change only because they persist through the acquisition of new properties; without that assumption we just have the same old particles (in new configurations) exemplifying the same old properties. Invariance is the basic rule: invariance under variation of position for particles and invariance under variation of distribution for properties. The fundamental units of reality never alter their intrinsic nature. The empirical world is more like the mathematical world than we realize. And notice that particles and properties are not entities of the same ontological category, since particles are particulars and properties are universals. Permanence is not the prerogative of universals, pace Plato; material particulars in space have it too. The two contrasting pillars of reality are both eternal immutable entities, which together allow change to enter the world. We can imagine a world with mutability all the way down (at least we think we can)—both the particles and the properties undergo intrinsic change—but that is not the world we live in. Change lies in the superstructure not the fundamental entities. How necessary is this? How much were God’s hands tied?
 The same is true of space: volumes of space don’t undergo change; they are the same after occupancy as before. Space is like a giant changeless homogeneous receptacle. This seems challenged by Einstein’s General Relativity, but the change envisaged is of a peculiar a kind, since no mark is left on space by gravity. But I won’t try to discuss this further. The basic cases of change are located perceptible medium-sized material objects.
 We are mortal beings surrounded by immortal beings, constantly changing in a world full of changeless entities. Not only do we die; other things are spared that fate. Surely this affects our view of death: what if we lived longer than any other entity in the universe? It is the thought of other things continuing, sometimes indefinitely, that makes our own lives seem tragically abbreviated, cruelly short. Plato died long ago, after a brief existence, but his universals are still with us and will be there after we are gone (same for the physicist’s particles). We are nature’s pinnacle (we think) but nature doesn’t care to keep us around for long, though it grants extreme longevity to the meanest of things. This seems perversely wrong, a kind of preposterous miscalculation. We are absurd because shockingly brief (“Out, out, brief candle”).