# How does one determine the boundary of an object?

Say we have what we would call an 'object' made of many components, can these 'components' be named objects themselves? In the case do we have an object or many 'objects'? Do we define an object to be 'isolated' things? Is it a choice how we express whether we have one or many 'objects' if they form a greater whole? Or is it more of a linguistic thing? Such as the idea of the question that 'is a Rubiks cube on cube or many cubes (attached together), which we could argue is more of a 'linguistic' issue?

It's a pragmatic thing more than a linguistic thing.

• If you want to go to the store, you think about your car
• If your car won't drive, you think about what part of it is at fault: engine, transmission, wheels, etc
• If you're trying to fix one of those parts, you think about its parts (the wheel's hub, tire, or axle; the engine's pistons or cranks; the transmission's gears or clutch...)

If you're merely driving around there's no sense thinking about all the various parts and mechanisms of the car. It's a car, and that's the only thing you need to know. We pick the level of analysis we need for the pragmatic task at hand, and that determines which things we constitute as undivided objects.

• The term for this is "levels of abstraction". Commented Apr 30, 2022 at 13:38
• "If you want to go to the store, you think about your car" ? Commented May 1, 2022 at 19:59
• @njzk2: In the sense that you don't think about the parts of your car. You don't think; "I need to get the assembly of wheels/engine/transmission/windshield/etc and go to the store". You think: "I need to get the car and go to the store." Commented May 1, 2022 at 21:07
• If you want to go to the store you should think about the store. When you realize that you live in a car-cult suburbia, and your car is the only way to get to the store, then you think about your car. I walk to the store. Commented May 2, 2022 at 9:15
• @user253751: Well, i'm extremely happy for you, but for the purposes of this question it doesn't matter whether you (personally) fly to the store on wings of desire or ride your pet marmot to get there. This is an illustration of a point, not a condition of life; don't nitpick. 😛 Commented May 2, 2022 at 10:06

Disclaimer: concepts from my last book, I do Systems research. This is related to the Systems Theory.

1. The object is the counterpart of the subject, being both the members of an interaction. An interaction implies a relationship between two systems, which is a bit long and complex to describe here. Object and subject are just two archetypes of systems. There is no object without subject and vice-versa.

"The rock is heavy" implies an interaction between a subject (the observer) and an object (the rock). Language always imply in a sentence that the subject is the observer. The imperative sentence "Sleep!" is an equivalent of "I-subject ask/command you-object to sleep". The sentence "That's a nice bike" is equivalent to "That bike-object is nice for me-subject". The sentence "one plus one is two" means "I-subject recognize the object-[one-plus-one is equal to two]", etc.

1. Absolutely all systems are ideals. Therefore, the object is always an ideal, a rational construct. For example, the moon is something we can't touch, explore. We just have the subjective ideal of the moon in our heads. Take a rock, and the situation is similar. A rainbow is the same.

2. The universe is constant change, there is literally nothing, absolutely nothing, radically nothing that is static. Everything changes. But our mind makes it appear as static. You change every second, the person you are looking in the mirror is not the same that was one second ago, the river is never the same.

Now, this is really amazing: not only our mind makes us perceive objects as static, but also our bodies. We are tuned to perceive the phenomena we perceive.

Thermodynamics differenciates such perspectives, the changing reality, and the apparent staticity as "microscopic" and "macroscopic".

1. Now the answer to your question becomes evident: the boundaries of objects (or things, when we refer to its physical façade), are macroscopic: defined subjectively by our mind and by our body. A rainbow has no other boundaries than those that our body and our mind grant to it.

Consider the case of a truck of apples in multiple states: immature, mature, rotten, broken, of different varieties, etc. It is literally impossible for two persons to count the same number of apples. And if both enter into a very detailed and strict definition of what is an apple, the definition is still subjective for those two persons. Any person will count a different number.

The subjectivity of our mind to define the boundaries of an object (e.g. Where does a tree starts and where does it ends) is easy to grasp. But not the physical subjectivity, the subjectivity of our body. Just think that aliens might be made with different physical structures and their hands can pass through walls. In such case, their perception of mineral-objects would be completely different, they would evidently unable to define boundaries on everything mineral on earth.

• You sound just like Heraclitus!!! : ) Process philosophy is liberating, isn't it?
– J D
Commented Apr 29, 2022 at 23:41
• @JD hope not :) This perspective is not precisely sustained on process, but mainly on substance, which is not a metaphysical issue, but a transcendental (in the kantian sense) condition. Phenomena is mostly substantial, not processual, and the noumenon... impossible to know, by definition. Commented May 1, 2022 at 4:54

I think it’s largely a linguistic thing, since the object/objects is/are what they are however we describe them. A more intriguing question (for me anyway) is that if you dismantle a Rubik cube into its component parts, where did the cube go. I digress. The idea of an object is typically thought of as a physical manifestation of a recognisable concept such as a chair and it’s entirely valid that this could be made of other objects and/or a part of a greater object. If you have a different definition of what constitutes an object then the answer may be different.

It depends on your metaphysical presuppositions. Philosophers have wildly different ideas on how to determine what a thing is. Pragmatically, one can resort to picking something up and seeing if it falls apart. Rationally, one can draw the conclusion, as in mereological nihilism (SEP) that macro objects don't exist at all, but there's merely object-like configurations of things. Sometimes it doesn't even require fancy logic. We all have noses, right? Where does the nose end and the cheekbone begin? To some extent, what a nose is somewhat arbitrary, and different language communities might have different definitions.

### Spatiotemporal Boundaries and Identity

Your question is intimately linked to ontology, because it asks after the structure of things that exist. In Western philosophy, there's is a bias to seeing 'objects' as static things with clear cut boundaries and definitions. A baseball is not a basketball and that's because both satisfy certain criteria of sufficiency and necessity. Science often provides elaborate procedures to define and measure boundaries, a hallmark of physicalism as a philosophical disposition. For instance, boundaries in STEM fields are often stated by precising definitions or are incorporated into operational definitions. In CAD, a screw may have a dimension listed with a tolerance measurement. Thus, everything inside the measurement, made of metal is the screw, and everything outside the measurement and not made of metal is not the screw.

But an astute student will start asking some clever questions. What about rust? If an iron screw IS the object and the atmosphere around it is NOT the object, when the oxygen combines with the iron, is that corrosion part of the screw or something external to it? Again, pragmatically, we can tap the screw, and whatever is left after the rust flakes off can be divided into screw and not-screw. This is fantastically useful, and has been going on more or less since Aristotle. But even with this physicalist philosophy, problems emerge. For instance, it turns out, that particles are also waves with an infinite distribution through space existing as a distortion in a field. To a philosopher of physics, then, objects can't be measured with certainty because they have inherently fuzzy, probabilistic boundaries. Stranger still, wave forms have the ability to pass through 'solid' boundaries as in quantum tunneling. From WP:

Some authors also identify the mere penetration of the wave function into the barrier, without transmission on the other side as a tunneling effect.

Hence, in this sense, spatiotemporal boundaries of objects are fuzzy and overlapping, more like sound waves that blend together as in a conversation, than legos that neatly compartmentalize into set-theoretic partitions.

### Questions of Discernment and Membership and Normativity

Talking again about noses, does everyone have the same definition of a nose? Does an ear-nose-throat doctor conceive of a nose in a fundamentally different way? Yes and no. Again, where is the boundary between the nose and the rest of the face? Here we see elements of the sorites paradox. In the explanation, the question is when does a grain of sand become a pile of sand by the addition of more grains? Easily one grain is not, and many are, but at some point, when does the pile exist? Two grains? Ten? One thousand? Now here's the difficult part of some people to grasp.

The simple answer is that the object 'pile of sand' is somewhat arbitrary. For one who pours concrete, a pile might measured in pounds, and for a manufacturer of sandpaper, maybe in fractions of an ounce. In a sense, a pile of sand is very intuitive, and any attempts to explain what a pile of sand is a convention and therefore normative. But you object! Clearly a pile of sand is a physical object, and everyone knows that objectivity means there must be one agreed upon object, else objects are subjective. Welcome to philosophy and please take moment to review this article on intersubjectivity. In a sense, definitions of even physical objects are actually intersubjective, because language itself is normative.

But that can't be! A car is a car is a car. A game is a game is a game. Yes, and no. (Also, meet another philosophical friend called dialetheism.) Besides mind-boggling quantum physics, philosophers of the twentieth century began exploring language in more depth realizing that categorizing groups of object is likewise mercurial. Leading the charge is Ludwig Wittgenstein and his notion of family resemblance. And from that, the science of language has produced the idea of the prototypical definition along with fuzzy logic have blurred the lines of identity and membership quite literally.

## Summary

What an object is and isn't to some extent is a convention. The best way to simplify that idea is to use the example of a picture of a red apple on a green background. Can you picture it? The apple is the red pigment and the green pigment is the field. But no one can really draw an exact line between the two. Anytime one zooms in and attempts with a finer pen, someone else can zoom in more and find a better outline, until ultimately, one is dealing with molecules and atoms who have no distinct boundaries. (Orbitals of electrons, the "outside" of a molecule in the modern sense, are probability distributions of wave functions.) But as much as people might dispute the boundary (philosophers in our extended metaphor), most people get a long quite fine, right? That's because most people just agree to agree there's some red and its not green. Unfortunately for red-green colorblind people, sometimes the community fails to see that their "objectively real" red apple isn't even visible to a minority. They might mock them, might tell them they're crazy or stupid not realizing the object "apple" is actually a convention of language that a person who can't experience it is blind to. In this way, even ordinary objects (SEP) are difficult to explain.

As a physicist, and from that perspective only, the question is arbitrary. Within a system, in physics, we often 'draw' imagined dotted lines around parts of that system and regard them as independent, separate entities - and then seek the rules that apply to each individual element. In this way, the system (or object), becomes a combination of parts. And each part, or element, can be regarded as a separate entity, consisting of that which is within the 'dotted line' and that which is without. i.e. what is without the dotted line is the entire universe!

So a rusty nail could become i. The intact metal, surrounded by a dotted line, interacting with the rest of the universe. (Likely the rust layer) ii. A rust layer, again bounded by an imaginary dotted line, interacting with the rest of the universe (e.g. the intact metal, and the atmosphere, and iii. the rest of the universe. As such, there is no real need to define a single object.

• Yup, another physicist here. I'd put it even more concisely: a theory defines objects whose evolution it then describes. Is gravity a force? Oops. No theory, no objects. And boundaries are defined only if the theory needs them, it may be a non-question. From the scientific POV, this question demands a clarification: in which theory? Philosophy is of a great value, however, when we have no theory, or when we want to recognize that no theory (not even all theories taken together) is a complete map of the territory... Commented May 2, 2022 at 6:15
• Agreed. I suggest it is a philosopher's 'non-question' and based purely on semantics. A rusty nail is an easy enough semantic concept for all of us, but actually consists of components and purpose, such as the form to make it a nail, and its intact metal, and its rust layer. If the rust layer component overwhelms the nail and its function, it becomes a pile of rust, and not a nail.
– Nick
Commented May 7, 2022 at 15:18

The obvious thing is that there is no clear boundary.

The case of living organisms in this discussion is particularly interesting. I am Peter, a material "object", in a broader sense. But what exactly is part of me? My skin? My hair (which is dead matter)? My saliva? The urine in my bladder? The contents of my intestines? The microbiome thriving in it, and on my skin? "The human body contains trillions of microorganisms — outnumbering human cells by 10 to 1. " Many of them are essential for my well-being, and a pre-modern description of "self" would probably count all of that as part of a person because it resides within the physical boundary of their body. But being modern, we may not consider the urine an actual part of the organism. But then, why should the blood in my veins be?

If we think that objects should be somewhat persistent through time, things become even more complicated with organisms because they exchange large parts of their constituting matter over time. This leaves us in a "Ship of Theseus" situation. Heraclitus was fully aware of it: We never step in the same river twice, but we also never talk to the same person twice.

So if the boundaries of a living being are so ill-defined in terms of a physical object, what are we? Why can we maintain such a strong sense of identity? What, in the sense of the word, defines us?

The invariant which is maintained — which constitutes our identity — is our structure. The connections our brain has formed, the placement and shape of our body parts, the memories of past infections imprinted in our T-cells. Our DNA. We are not a specific lump of matter: We are a self-replicating pattern traveling through time. We are a resonance imprinted on matter rather than a fixed, static "object".

Structures, patterns that share commonalities independent of the specific underlying "substrate" they emerge from, have been recognized as their own field of research — Systems Theory — only in the 20th century.

This angle which looks at structures rather than matter, relations rather than entities, closes the circle and allows us to answer the original question:

Objects are systems.

A system is a collection of interacting parts whose inner coherence is strong compared to its connections to its environment. That's something all trivial objects — stone, paper, scissors — share: We can pick them up and they retain coherence; we can move them more or less in one piece and put them back down. There is no need to be absolute here: I lose a few molecules of myself wherever I am, but it's really little compared to the other 1028 molecules that stick together really well, microbes or not.

This definition works very well for inanimate objects as well: A handful of powder snow is probably not an object: Its inner coherence is too low. A snowball though is, until its existence comes to an end in somebody's face. A wooden plank is an object as soon as we have separated it from the trunk of a tree, but not earlier when its coherence with its surroundings was too strong.

The systemic approach is fertile. It allows us to recognize certain collections of objects as single objects, something a purely static approach may have trouble to justify: Particles form atoms, atoms form molecules, molecules form cells, cells form complex organisms, organisms form hives, states and peoples. We are part of a planet, part of a solar system which is clearly an object even though the coherence is entirely immaterial, because it is still relatively strong compared to its interactions with its surroundings. The same is true for the Milky Way, our local group and ultimately, presumably, the universe.

Objects which consist of interacting components are called systems. A car object is a system since it has many components like the breaking system, the engine, the indicating system.etc. Similarly an atom is a system since it contains protons, neutrons and electrons. Whether you interpret the object in question as a whole or as a system is up to you. You can interpret a car as a whole where it has functions like allowing you to get to work, or you can interpret it as a system where it consists of differing components interacting. Each component of a system can also be interpreted in the same way, as a whole or as a system itself, in this way systems are said to be hierarchic.

So an answer to the question of where the boundary is, is that there isn't one uniform way of determining where it is because systems can be quite abstract themselves. For example your TV set is a system which consists of a remote control and a set-top box, these two objects are clearly not phyisically near each other but are still a system that could be considered as one.

Here is a good description of systems https://www.scq.ubc.ca/systems-biology-an-overview/

I think objects have no boundaries, but humans can assign boundaries to objects based on their functionality.

Imagine we peel off all the paint from a world-renowned painting, and the paint and remaining paper would be worthless. However, before that, this painting could have been priceless. But this painting is indeed composed of these pigments and paper, why is it not worth it to peel them off from the painting? This is actually easy to understand. The value of this painting is determined by many bidders, and what they value is a certain idea or beauty expressed by the painter using these papers and pigments. Or rather, it is the specific arrangement and combination of these pigments based on this paper that makes this painting stand. Otherwise, these papers and pigments are no different from the sand in the desert.

In fact, people are the same. People are nothing more than specific combinations of different substances, different functions, and different trajectories of movement that distinguish them from others. And it is precisely these differences that give birth to a person.

Regarding the functionality of objects, there is an even older example called the Ship of Theseus: if all the wooden boards of a ship have been replaced, can it still be called Theseus? If these replaced wooden boards were used to build a new ship, which of the two ships should be called Theseus?

In fact, this question is not difficult to answer. Even if all the wooden boards of the original ship were replaced, it was still the Theseus, and the newly built ship, even if it was built entirely from the original Theseus wooden boards, cannot be called the Theseus. Because it is stipulated that the subjectivity of the Theseus is the combination of wooden boards, not the boards themselves. Although the new ship was also a union of wooden boards, it was another union of these boards, and the original wooden board union, the Theseus, did not disappear. Even if the Theseus was dismantled and rebuilt, the newly built ship could only be a new alliance, and the old alliance had disappeared, so the rebuilt ship was not the Theseus.

So, I can say that the establishment of object boundaries relies on the combination of matter to establish functionality, and the disappearance of objects in our human mouths actually refers to the disintegration of material combination leading to the loss of their functionality. If it is a human, then the subjectivity of a person is the union of matter that creates the birth of human consciousness. The role of consciousness in humans is that it can enable this fleshy union to unfold life in some unique movement trajectory. If it is an organization, it is the birth of its mission that establishes its functions. With a clear mission, these organizations have the ability to take action.

And the ship called the Theseus was almost only fully displayed to its owner, so only its owner witnessed the establishment of its functionality and the full display of its boundaries. If it is demolished, then in the eyes of the shipowner, the ship will naturally have disappeared, even if it is rebuilt again.

This also means that if you do not witness the full process of the functional birth and disappearance of all things in the world that we come into contact with, then its boundaries are blurred for you.

What exactly do we remember when we say we remember certain people and things? In fact, due to the proximity of time and space, we cannot witness the entire process of others and other things. So, strictly speaking, even the closest people, our grasp of their boundaries is incomplete. What we can understand is just an impression. We mostly remember how he did something or speculate on how he will do something in the future based on it.

Our impression of an object is actually only about its shape. What is it composed of, when and how is its functionality established, how is it fully developed, and how will it disappear? We won't even know.

In theory, we cannot fully grasp the boundaries of any person or object, which is inevitable for people with great limitations.