Can anything really ever be identical?
By 'identical' I mean similar in every detail; exactly alike.
I've been trying to think about this while reading bits of other threads. I think everything is unique in some way or other. If two things appear to be identical they would still be different if they are in different locations for example. How could two things or more be in the exact same location? You might say 'all your eggs are in one basket' but each egg would be subtly different anyway. Even numbers are never identical, I mean one is not the same as another one because if there's more than one then they are distinguishable even if only by position. I dont think an item or concept could be identical with itself either, because things change over time and the only way I can imagine to prove something to be identical is by comparison. Maybe that's it..? Maybe things can't be classed as identical because you must always make a comparison? Or am I just waffling (again)?
I've been trying to think about this while reading bits of other threads. I think everything is unique in some way or other. If two things appear to be identical they would still be different if they are in different locations for example. How could two things or more be in the exact same location? You might say 'all your eggs are in one basket' but each egg would be subtly different anyway. Even numbers are never identical, I mean one is not the same as another one because if there's more than one then they are distinguishable even if only by position. I dont think an item or concept could be identical with itself either, because things change over time and the only way I can imagine to prove something to be identical is by comparison. Maybe that's it..? Maybe things can't be classed as identical because you must always make a comparison? Or am I just waffling (again)?
Comments (51)
There are several terms like this that transcend languages - the most obvious being numbers. In every language the number ‘one’ is the same number one not a different number ‘one’. That said, there is differences in each person’s lexicon and experience, so I may associate certain ‘universal terms’ like these with experiences that aren’t ‘universal’ - the meaning, in the purest sense of the term, does remain identical though.
As a rule of thumb any ‘abstract’ term - not concrete nouns - is identical, yet it’s use is rarely, or maybe never, used in an identical way (as above with the example of items listed). Remove items located in time and space and you’ll find many identical items of thought such as conjunctions and identifiers.
"What's the difference between a sparrow?
?
Both of its wings are identical, especially the left one."
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Someone said that if we count position and placement, then eSPECIALLY can't two objects be the same.
It is conceivable, however, that the wardrobe chest I just got delivered to my house made of compressed wood contains two identical wardrobe chests, both occupying the same space at the same time and in the same respect.
Like the morning and evening star, water and H2O, temperature and molecular motion, Samuel Clemens and Mark Twain, the empty set and 0, or the charge of every electron in the universe.
Or that damned ship that had all its parts replaced during its voyage.
There is a the one-electron universe hypothesis where all the electrons and positrons are just one entity traveling back and forth through time, thus explaining how they all have identical mass and charge.
Setting that idea aside, even if physical objects can't be identical, some properties do have that quality. Leading us to ...
Universals (or Tropes).
Always, invariably, in all circumstances.
Well obviously in each case, the terms on the left and right side do not possess the same sense, so are not practically substitutable, so are only substitutable in a theoretical sense that makes potentially falsifiable counterfactual claims. Now standard dogma alleges that Superman is only de dicto different from Clarke Kent, but that de re they are one and the same person.
" In the context of thought, the distinction helps us explain how people can hold seemingly self-contradictory beliefs.[4] Say Lois Lane believes Clark Kent is weaker than Superman. Since Clark Kent is Superman, taken de re, Lois's belief is untenable; the names 'Clark Kent' and 'Superman' pick out an individual in the world, and a person (or super-person) cannot be stronger than himself. Understood de dicto, however, this may be a perfectly reasonable belief, since Lois is not aware that Clark and Superman are one and the same. " - https://en.wikipedia.org/wiki/De_dicto_and_de_re
Yet in "Superman 3" Superman was poisoned and divided himself into Evil Superman and Clarke Kent who then fought a physical fight. I submit this as evidence that Superman is not Clarke Kent de re .
See identical particles which are indistinguishable in principle.
This is Leibniz' principle, "the identity of indiscernibles". It states that if two objects can be said to have the very same properties, then they are identical. "Identical" means having the same identity, and by Aristotle's law of identity, this means that they are actually one and the same object. Therefore it is incorrect to say that this is "two objects", because it is actually one and the same object being referred to. The law of identity, "a thing is the same as itself" represents the uniqueness of every object. Essentially, it says that an object is unique.
Quoting god must be atheist
You can say this, that two distinct things can occupy the exact same place, at the exact same time, but is this really conceivable? There is a difference between what you can say, and what you can conceive. To actually conceive of what you say here, you would need a conception of the spatial temporal existence of an object which would allow for this. I believe that "multiverse" theorists allow that the same object exists in many distinct universes, and multiverse theory is supported by the many-worlds interpretation of quantum mechanics. This allows one to say that the same object is many objects, separated by being in many universes. However, if the multiple wardrobes you refer to, are actually in separate universes, it would not really be correct to say that they occupy the same space at the same time, because the particular space and time being referred to is a property of the particular universe..
Part of a quantum particle's identity is that it can have amplitude for two or more positions (i.e., a superposition).
This is just a different notion of identity to the classical idea where particles always have a definite position and momentum.
What if it's not 'a different notion of identity', but that it's not an identity at all. There are not two things which are identical. It is said that particles aren't even particles until they're measured, prior to that literally all that exists is a distribution of possibilities. It's not as if there's a particle whose whereabouts is unknown, it doesn't have an exact whereabouts, so also does not have an identity. In fact couldn't you say that the measurement is what confers identity on it, by giving it a position and making it 'this particle'?
Correct. The presence of a difference precludes identicalness. Two objects are identical if and only if they both possess the exact same properties. This definition uses properties as defining elements of objects; objects here meaning anything and everything.
If you agree then imagine four objects A, B, C, and D and that there are only 4 possible properties: round, square, red and black.
A is a red and round
B is red and square
C is red and round
D is black and square.
Using "=" to mean "identical to" we conclude that A = C but A not = B and B not = C and so on. Identicalness, in this sense, means all properties must match exactly.
Bear in mind the identicalness is not the same as identity. The former is a relationship between objects as we've seen above but the latter is not. Identity is, as you so rightly noted, uniqueness which in mathematical terms is one and so, because relationships require at least two objects, identity isn't a relationship.
To further clarify the difference between identicalness and identity we need to understand that identicalness doesn't consider space-time properties as relevant to its meaning. That's why when we're presented with two cars of the same model we usually say that they're identical. That the two cars occupy different spatial location is not relevant to identicalness. Similarly that one car was produced five minutes after the second car doesn't matter so long as they're the same model. In short space-time properties are irrelevant to the concept of identicalness.
When it comes to identity, matters are different and space-time properties are critical to its meaning. One object cannot occupy two locations in space at the same time and it is this impossibility that gives objects their identity. So, two/more objects can be identical because they share all properties except space-time properties but they all have different identities because one object can't occupy two locations in space at the same time.
Quoting believenothing
If we look at how I defined identicalness then it's true that any object possesses all the properties it has and so it follows that an object is identical to itself.
Remember I said earlier that relationships require at least two objects. This isn't entirely true as is evidenced by the claim above that a = a or A = A but this can be understood in terms of identicalness in identity being only reflexive - oneness preserved.
This is codified in logic as the law of identity as a = a for objects and A = A for propositions.
This is necessary for the reason that in any discourse the meaning or words and sentences shouldn't change otherwise humorous but dangerous events will occur. For example this could happen:
1. Only man is intelligent
2. No woman is a man
So
3. No woman is intelligent
In the above argument the meaning of "man" has changed from "humans" in 1 to "male" in 2 which leads us to wrong albeit funny conclusion. The law of identity exists to prevent such things from happening.
Quoting armonie
:up:
Quoting god must be atheist
:lol:
Quoting Metaphysician Undercover
Read my reply to the OP
It's not so straightforward. While a position measurement makes the position definite (within the measured range), it also makes the momentum indefinite (i.e., the particle is now in a superposition of momenta). So the state of a particle always has at least some indefinite properties (due to Heisenberg uncertainty), regardless of whether the particle is measured or not.
Yes, I would just add that this depends on how the object is defined. For example, in a sense it is true that my desk can occupy two locations in space at the same time - one leg here, another leg there! That's because the desk is defined as an object that is extended in space. But if by "location" we mean the spatial extension of the desk then it is true that the desk cannot occupy two locations in space at the same time - because it would violate the definition of the desk and so we would be talking about a different object than a desk.
This should be kept in mind when interpreting quantum mechanics. There is no point particle that occupies two points of space at the same time, but there is a quantum wave, defined as a spatially extended object, that occupies two or more points of space at the same time. Alternatively (and equivalently, if I understand it correctly), there is a point particle that occupies two points of space at the same time if the definition of the "point particle" allows the particle to move not only forward but also backward in time.
As far as I understand the quantum wave is just the probability of where a particle is located. That there are two different locations in the probability doesn't imply the particle is in different locations at the same time.
Imagine an escaped convict being hunted by the law. The search party would need a plan to find the escapee and it could take the following form: he needs water so he maybe along the river; he needs to avoid detection so he may be in the forest; he needs food so he maybe around a town; etc. There's a probability that he maybe in all of these locations but that in no way implies he's in all of them at once at the same time.
Right. Which is to say that it has no definite identity. Which is another way of calling into question its actual existence. Which in turn has a lot to do with the whole Einstein-Bohr debate.
Do you mean that the particle has a position in a point of space like the escaped convict and the quantum wave is only an expression of our incomplete knowledge of the particle's position? This idea was refuted by experimental tests of Bell's theorem: no local hidden-variable theory can be a correct description of quantum mechanics, where the hidden variable is a single point position of a particle, for example. This doesn't rule out non-local hidden-variable theories such as Bohm's but these theories seem incompatible with special relativity because they introduce superluminal speeds.
The more important question, perhaps, is what constitutes a thing. Who decides what constitutes a thing? Us, of course.
Let's say we have two apples both of which are completely identical except in one regard: they occupy different positions. Are they identical or not? The answer depends on whether an apple's position constitutes its identity. In general, the answer is no, since we all operate with the concept of apple according to which an apple remains the same apple regardless of its position in space. Therefore, we can conclude, the two apples, though occupying two different positions, are identical.
Quoting believenothing
In most cases, that amounts to sophistry, since position is rarely part of an object's identity.
Identity can also be (and it mostly is) established by history. So two objects can occupy the same position in space at the same time and still be identified as two different objects simply because they have different histories.
We can also define the identity of an object by its relations to all other objects. The object's parts are only some of the other objects. Since the two apples have different positions relative to other objects, they have different identities. If they had the same positions relative to all other objects, they would have the same identity, which means they would be one apple, not two.
My point is, not necessarily.
In general, history is very important. Have you heard of Richard Gregory's top-down theory of perception?
As far as scientists can tell, all physical systems are quantum and so will produce the same quantum behavior as microscopic particles (one example is a visible piezoelectric tuning fork comprising about 10 trillion atoms). So the issue of identity and existence applies equally to large systems as small.
No, but I take history into account by including in the definition of an object the object's position in spacetime.
Language doesn't work in the way presumed here. The meaning of terms such as "identical' changes with its use - or rather, we should think of its use rather than its meaning.
So Venus is variously called Phosphorus in the morning sky, Hesperus in the evening sky. Are they not identical?
1+1 = 2. And one plus one equals two. Are these equations - one in words, the other in numbers - identical?
One could continue citing examples of such equivocating expressions. THe point is that it depends on what you are doing.
By not paying the attention due to the language being used, the replies here amount to nothing.
Like most of philosophy.
I agree. Particles effect human action and a pair of identical twins with out a doubt have particles in different locations despite the fact that their dna is identical or close to identical. Even if the difference is what would commonly be called a trace difference. (such as humans have a trace amount gold in their bodies). If one twin wore a gold ring and the other didn't, one would probably have slightly more gold in his/her system. Gold to some extent is good for the human body.
Fantastic, thanks a lot. I often struggle with conventions though. I should say I struggle with language more often. I feel relieved to find I was barking up the wrong tree.
If you read the same thing in two different books, such as a quote, then let me suggest you have seen the same 'idea' twice or in other words two identical ideas - all be it from different sources. Also 1+1=2 is something that will appear many times, so it's also kind of a repeated idea or identical idea. I'm not sure how to explain my perspective.
It seems I don't really spend enough time contemplating things in order to be able to contribute much to this site. I'm trying to dable though. Whether responses on this site amount to nothing or not, I'm glad this site exists and people still have time to share things on here.
I think I will continue to enjoy reading from my replies as long as I have breath.
Thank you for the clarification. What I actually meant was just as after the search is actually conducted and the convict's location is discovered s/he will be found in one location, the particle too will be localized to one location. It isn't the case that quantum theory is claiming the particle is in two or more locations at once: the quantum wave merely indicates that the particle's position is uncertain. IF the quantum wave is actually saying the particle is in more than one location at the same time then why do we need probability in the first place? Simply say that the particle is in whatever location and also in another location.
I agree but only partially because history isn't exact enough as the requirement that it's impossible for one object to be in more than one location at the same time. Imagine two paintings A and B that are in the same gallery and is the work of the same artist. The histories of both A and B are identical and that, if history defines identity, would mean A and B have the same identity which strikes me as preposterous. Every relevant parameter could be manipulated to make A and B have the exact same history and yet it wouldn't feel right to say A and B had the same identity.
I see the quantum wave as an object whose mathematical (quantitative-structural) properties specify how it will interact with other objects. I don't mean that a quantum wave is less "real" than a point particle; it's just something that is there, although a different something than a point particle. The probabilistic character of the quantum wave is of course at the heart of interpretations of quantum mechanics. Currently I prefer the many-worlds interpretation because it doesn't seem to need more assumptions beyond the Schrodinger equation of the quantum wave, like wave "collapse". It just assumes that the quantum wave evolves according to the Schrodinger equation, with the mathematical consequence being that when the wave interacts with a many-particle object, parts of the wave that correspond to different possible values of a variable (for example, point position) stop interfering with each other and become separated into non-interacting parts of reality ("worlds").
A problem with the many-worlds interpretation is that an infinite number of possible values of a variable corresponds to an infinite number of worlds and it is not clear how to calculate frequentist probabilities when there is an infinite number of possibilities. Maybe a reconciliation of quantum mechanics with relativity theory will provide a solution to this problem, perhaps by limiting the number of possibilities to a finite number.
This is an incorrect example because of the deficiencies of the human capacity of identification. The law of identity places a thing's identity within the thing itself, (a thing is the same as itself), not in what we say about the thing. So A is not necessarily the same as C because your premise "there are only 4 possible properties" is a faulty premise.
I think that metaphysical identity deals with physical identity. But even aking your example, reading the same thing at 3 am would evoke a different image/interpretation than reading it at 3 pm.
https://en.wikipedia.org/wiki/Law_of_identity
If you are then exactly what are you talking about that isn’t covered by this law? Identity is necessary for identifying - the idea of ‘identical’ is pretty much the basis of propositional logic and the means for common communication rather than having a constantly shifting perception of reality that remains wholly distanced from the next moment, person or thought.
Much like the question of ‘what happens when an unstoppable force meets an unmovable object?’ The answer is so startlingly obvious we don’t appreciate it straight away. The answer is we either don’t ‘see’ what happens, or we reestablish our concepts for ‘unstoppable’ and ‘unmovable’ - perhaps identifying a new concept to explain the phenomenon (a modern example would be the phenomenon of quantum - we name it and then investigate further to identify what is happening).
The issue is an epistemic one.
I only used 4 properties to simplify the issue and the number 4, in and of itself, has no bearing on the critical aspects of identicalness which is, quite obviously, based on shared properties. The only method by which we may distinguish objects is on the basis of differences in properties and the only method by which we may say two or more objects are identical is by checking if they share all properties or not.
As you can see, any interpretation, wave collapse or many worlds, is clearly born of the difficulty in accepting that one object can occupy different locations at the same time or some variation of that theme. Wave functions collapse and the particle is detected in one of the many locations instead of being at all of them at once. Many worlds exist precisely because each possibility would require a different location to be actualized.
The point was to show that your approach is faulty. Identity is based in uniqueness, and this is the opposite of "shared properties". So you'll never get to the true meaning of "identical" through the assumption that "identicalness" is based in shared properties, because it's not, it's based in "identity", and identity refers to uniqueness..
"Can anything ever be identical?
Beyond the necessary truism that everything is self-identical, methinks the answer is no.
Firstly we seem to be on the same page. Secondly you didn't read my post but that's ok because there's nothing that isn't obvious in it.
thanks, i think. I was just telling a friend i might have some reading to do. That was before I logged into this site, spooky eh? I'm not so sure what I do with my time. So called book knowledge was never my forte. Too many alternatives- i mean alternative books and/or sources. I still think too much knowledge can be a bad thing.
Does it mean I am myself? My first name starts with an "A".
Then what happens when I'm beside myself? Am I still identical to myself?
Or let's suppose I cloned myself. On the other hand, let's not suppose that.
Knowledge is power. And don't you forget that.
Power is something else.
Something else is something else again.
And don't you forget that.
This is the most powerfully useful idea in all of philosophy.