Criteria of 'Existence'

[Nihilist]

It seems a lot of disputes have at their heart disagreement about what constitutes ‘existence’ (e.g. does God exist, does the soul exist, etc.)

Now, what would be the definite criteria for existence, such that, if X meets them, I may say, “X exists”.

My proposal is that the criteria might be the occupation of space and/or time. Some things (people, rocks) ocuppy both space and time, and truly ‘exists’. Other things, like thoughts and actions (and thus the mind) occupy only time, without space, but are also truly said to ‘exist’. Things like abstract concepts do not occupy either space nor time, and therefore do not exist in themselves (although the ‘act of thinking them’, as occupying time, does exist)

Perhaps its just a matter of linguistic convention, but it would seem useful to have a precise criteria for existence. Can someone come up with a good definition?

 

[seagal]

If the criteria that something exists is the occupation of space and/or time that lets out God, the angels, the devil and all evil spirits, not to mention our souls, without which we have no life.

 

[Oreoracle]

Now, what would be the definite criteria for existence, such that, if X meets them, I may say, “X exists”.

My proposal is that the criteria might be the occupation of space and/or time. Some things (people, rocks) ocuppy both space and time, and truly ‘exists’.

I would tweak this criterion slightly. I think the object has to exist in such a way that the claim “X occupies space and time” is falsifiable.

This reminds me of our discussion in an earlier thread. Movements within the Planck length are so minute that they cannot be observed, but can only be inferred indirectly. If they couldn’t be inferred even in an indirect manner, then I would argue that the claim “X has moved” has no meaning. It’s only because motion is well-defined that we are able to falsify such claims.

Other things, like thoughts and actions (and thus the mind) occupy only time, without space, but are also truly said to ‘exist’.

I’m not sure what you mean here. Space and time are part of the same continuum of spacetime, no? To occupy one is to occupy the other.

Things like abstract concepts do not occupy either space nor time, and therefore do not exist in themselves (although the ‘act of thinking them’, as occupying time, does exist)

I think these usages of “exist” are conventional and differ from the more standard usage. To say, for example, that a solution to an equation exists is to say that there is some object within one’s axiomatic system that fulfills the conditions specified by the equation. Objects “exist” insofar as they can be constructed or inferred from the axioms.

 

[Nihilist]

If the criteria that something exists is the occupation of space and/or time that lets out God, the angels, the devil and all evil spirits, not to mention our souls, without which we have no life.

But our souls do occupy time- since our thoughts, desires, etc., (the movements of the soul) are locatable in time.

I know it is often said that God is outside of time- but wouldn’t it be better to say God is everywhere in time, since His actions are necessarily locatable in time?

Since all action takes place in time, it follows that any agency capable of action is locatable (although not confinable) in time.

 

[Nihilist]

I would tweak this criterion slightly. I think the object has to exist in such a way that the claim “X occupies space and time” is falsifiable.

This reminds me of our discussion in an earlier thread. Movements within the Planck length are so minute that they cannot be observed, but can only be inferred indirectly. If they couldn’t be inferred even in an indirect manner, then I would argue that the claim “X has moved” has no meaning. It’s only because motion is well-defined that we are able to falsify such claims.

I’m not sure what you mean here. Space and time are part of the same continuum of spacetime, no? To occupy one is to occupy the other.

.

I largely agree.

But its seems something can occupy time, without space- like a thought- it has no physical extension, and therefore does not occupy space, but it does occupy time.

Perhaps ‘locatability’ (whether this is understood spatially, temporally, or in some other sense) could be a criteria for existence?

 

[Oreoracle]

But its seems something can occupy time, without space- like a thought- it has no physical extension, and therefore does not occupy space, but it does occupy time.

I think thoughts do occupy space; namely, in our brains. The way we use language reflects this. We do not talk about thoughts apart from the beings that have them. We instead talk about your thoughts and my thoughts. We occupy space, so the spatial component is implied.

I suspect that you won’t be satisfied by that, so let’s use the falsifiability criterion: Wouldn’t you need to know where a thought occurred for the claim of its existence to be falsifiable? I would count attributing that thought to a thinking being (your thought, my thought, etc.) as information about where it took place.

 

[inocente]

It seems a lot of disputes have at their heart disagreement about what constitutes ‘existence’ (e.g. does God exist, does the soul exist, etc.)

Now, what would be the definite criteria for existence, such that, if X meets them, I may say, “X exists”.

My proposal is that the criteria might be the occupation of space and/or time. Some things (people, rocks) ocuppy both space and time, and truly ‘exists’. Other things, like thoughts and actions (and thus the mind) occupy only time, without space, but are also truly said to ‘exist’. Things like abstract concepts do not occupy either space nor time, and therefore do not exist in themselves (although the ‘act of thinking them’, as occupying time, does exist)

Perhaps its just a matter of linguistic convention, but it would seem useful to have a precise criteria for existence. Can someone come up with a good definition?

Your use of space/time doesn’t work, as for instance an idea occupies neither.

You would also need to show that spacetime is more fundamental than absolutely anything else, and physicists might raise their eyebrows at that.

I think the normal definitions are that something which exists independent of any given mind is called an object, which is concrete if it occupies spacetime (exists physically) and abstract if it doesn’t; while something which only exists in a mind is subjective. So existence would be along the lines of having an objective or subjective reality or being.

 

[polytropos]

I would tweak this criterion slightly. I think the object has to exist in such a way that the claim “X occupies space and time” is falsifiable.

This reminds me of our discussion in an earlier thread. Movements within the Planck length are so minute that they cannot be observed, but can only be inferred indirectly. If they couldn’t be inferred even in an indirect manner, then I would argue that the claim “X has moved” has no meaning. It’s only because motion is well-defined that we are able to falsify such claims.

This seems like an odd position. How would you handle the case that our observational capacities change?

Suppose someone (say, one of the early corpuscularians several hundred years ago) once said that atoms are materially simple, non-compositional. This statement could not be falsified then. Now it can be falsified; we know that atoms are composed of subatomic particles.

But that fellow hundreds of years ago was wrong. It wasn’t that his statement had “no meaning”–it’s that he was wrong.

One could say that perhaps the claim was falsifiable, because now we falsified it. (In other words, a proposition is falsifiable if it can be falsified at some time, past, present, or future.) But then your example with the Planck length falters, because it might be falsifiable in the future. Then we have an epistemological implosion: we don’t know what will be falsifiable and when, so the theory of meaning becomes vacuous.

The source of this issue is that claims that falsification is a very odd criterion of meaning, anyway. We should expect issues in that it appears one would have to understand the falsification criterion for the claim to be taken that way. Otherwise, people who are not familiar with the boundaries of current natural science will quantify over entities falsifiable and non-falsifiable–clearly, whichever they are makes little difference to them. But if they are indifferent to the distinction, then it seems like all of their statements are meaningless–the external criterion, completely apart from their linguistic practice, can’t distinguish them. So the odd result is that people who don’t understand the criterion simple speak nonsense. I think that consequence would invalidate the idea that falsification is a necessary condition for meaning.

 

[Oreoracle]

This seems like an odd position. How would you handle the case that our observational capacities change?

Suppose someone (say, one of the early corpuscularians several hundred years ago) once said that atoms are materially simple, non-compositional. This statement could not be falsified then. Now it can be falsified; we know that atoms are composed of subatomic particles

This is a misunderstanding of falsifiability. To say that a statement is falsifiable is to say that there is a conceivable scenario in which one could observe something that contradicts the claim. It deals with what is observable in principle, not what is practically observable given our technological capabilities.

The criterion of falsifiability is there to prevent people from claiming things like “I have a pet leprechaun at home. Oh, you want to see him? Sorry, he’s invisible. He’s also mute and ethereal. Is there something you can observe that only his existence would explain? Well, I have this pot with a gold coin in it at my house. I could get that from the store and from collectors, you say? Well, now you’re just being picky.” The issue is the ability to endlessly detach the entity from the phenomena it’s intended to explain.

Compare this with String Theory. The claims of String Theory are currently untestable due to technological limitations, but they aren’t unfalsifiable. The claim that the Higgs-Boson existed was also falsifiable/verifiable even though it was untestable for a long time. We knew that it was verifiable before we actually verified it.

As for the relationship between falsifiability and meaning, I think unfalsifiable claims tend to be nonsensical. What would it mean to have an invisible, mute, ethereal leprechaun? What would the existence of such a thing imply? What is different about the world because of its existence? I don’t think such a claim is even asserting anything that is intelligible. If it were, then surely we could conceive of a way to prove/disprove it, at least in principle.

 

[Partinobodycula]

My proposal is that the criteria might be the occupation of space and/or time.

And how do you propose to prove that space and time exist?

 

[polytropos]

This is a misunderstanding of falsifiability. To say that a statement is falsifiable is to say that there is a conceivable scenario in which one could observe something that contradicts the claim. It deals with what is observable in principle, not what is practically observable given our technological capabilities.

This does not avoid the epistemological implosion I mentioned. We know what is observable according to our current technological capacities, but we do not know what is observable in principle. But meaning is a function of current linguistic practices (there are no linguistic practices “in principle”).

The criterion of falsifiability is there to prevent people from claiming things like “I have a pet leprechaun at home. Oh, you want to see him? Sorry, he’s invisible. He’s also mute and ethereal. Is there something you can observe that only his existence would explain? Well, I have this pot with a gold coin in it at my house. I could get that from the store and from collectors, you say? Well, now you’re just being picky.” The issue is the ability to endlessly detach the entity from the phenomena it’s intended to explain.

OK, I get that. The issue is that criterions for meaning have nothing to do with preventing people from making ridiculous claims. (When you say “has no meaning,” what do you mean exactly?) I think most people would be willing to say that the leperchaun-postulator is wrong. (I think he is wrong. Maybe he’s right and we just can’t tell. But there is no need to introduce some “lack of meaning” that is clearly unrelated to the phenomenon of “meaning” in general.)

As for the relationship between falsifiability and meaning, I think unfalsifiable claims tend to be nonsensical. What would it mean to have an invisible, mute, ethereal leprechaun? What would the existence of such a thing imply? What is different about the world because of its existence? I don’t think such a claim is even asserting anything that is intelligible. If it were, then surely we could conceive of a way to prove/disprove it, at least in principle.

Well, this is interesting because it approaches an argument. One weakness is that it takes one example of an unfalsifiable claim, which is also apparently nonsensical, and then infers that other unfalsifiable claims are like it. (It goes without saying that this is not a valid inference.) We may regard the leperchaun claim as nonsensical for a variety of reasons–for example, we think of leperchauns as bodily, visible beings that can make noises, so if we eliminate those essential features, we seem to be left with nothing, or something with features that contradict its essential features.

So these considerations would not really tell us anything about how we should regard nonfalsifiable, nonobservable entities that we believe in to account for certain phenomena. For example, I think we have discussed one argument for the immateriality of thought before:

(1) Some formal thinking is determinate
(2) No physical process is determinate
(3) Therefore, some formal thinking is non-physical

To say that we don’t have an idea of what it means for something to be non-physical is a weak response to this argument. For surely everyone might admit that we are immediately acquainted with physical, observable things, and our conception of anything that might be “non-physical” is (prior to reflection) undetermined–maybe coherent, maybe not. If some argument forces that conclusion on us, then we simply know more about the world and understand that some coherent sense of “non-physical” exists. (Though in another sense, the non-physical thinking that this argument claims is coherent is falsifiable, for (1) or (2) could be argued against, and if we hold them to be true, we will do so because of empirical considerations, things we have learned from our sense experience.)

To go back to the relationship between falsifiability and meaning: I don’t think you’ve adequately addressed my points. For example, take a group of language-users who asserts things that are in principle falsifiable (assuming that this itself is unproblematic, which isn’t clear), but which they believe are unfalsifiable. They are therefore speaking nonsense. The ontology of their claims doesn’t matter; what they mean will be determined by what they believe. But this strains the idea that this could really be a theory of “meaning.” (It would also seem to entail that groups of language-users who make in principle unfalsifiable claims but believe them to be falsifiable are actually meaning something. It’s not like when I speak about subatomic particles, something in the world “makes” me mean something, whereas when I speak of the flying spaghetti monster, something “makes” me mean nothing. Linguistic practice and epistemology is what will determine meaning, not ontology.)

 

[Nihilist]

I think thoughts do occupy space; namely, in our brains. The way we use language reflects this. We do not talk about thoughts apart from the beings that have them. We instead talk about your thoughts and my thoughts. We occupy space, so the spatial component is implied.

I suspect that you won’t be satisfied by that, so let’s use the falsifiability criterion: Wouldn’t you need to know where a thought occurred for the claim of its existence to be falsifiable? I would count attributing that thought to a thinking being (your thought, my thought, etc.) as information about where it took place.

OK, but an ‘event’ in general occupy time, but not space. Take a sunrise. Now, the sun occupies space, but it is not the sunrise. The sunrise, as such, is not a physically locatable ‘thing’- it is rather it is a series of physical states, through time. The sunrise, therefore does not occupy ‘space’- since it is an ‘event’ (a series of physical states), not a physical object itself. So, it occupies only time. Obviously it has some relation to space.

Or perhaps saying ‘sunrise’ is just a manner of speaking, and all that really exists is the sun, moving through different states and locations?

 

[Nihilist]

Your use of space/time doesn’t work, as for instance an idea occupies neither.

You would also need to show that spacetime is more fundamental than absolutely anything else, and physicists might raise their eyebrows at that.

I think the normal definitions are that something which exists independent of any given mind is called an object, which is concrete if it occupies spacetime (exists physically) and abstract if it doesn’t; while something which only exists in a mind is subjective. So existence would be along the lines of having an objective or subjective reality or being.

Hmm… Isn’nt saying existence is having objective or subjective reality or being just a tautological paraphrase- since reality and being are basically just synonyms for ‘existence’.

Like saying, ‘being red is having subjective or objective redness or reditude’ (sorry for the last word!). Yet it doesn’t actually provide a criterion of ‘being red’…IMHO

 

[Nihilist]

This seems like an odd position. How would you handle the case that our observational capacities change?

Suppose someone (say, one of the early corpuscularians several hundred years ago) once said that atoms are materially simple, non-compositional. This statement could not be falsified then. Now it can be falsified; we know that atoms are composed of subatomic particles.

But that fellow hundreds of years ago was wrong. It wasn’t that his statement had “no meaning”–it’s that he was wrong.

One could say that perhaps the claim was falsifiable, because now we falsified it. (In other words, a proposition is falsifiable if it can be falsified at some time, past, present, or future.) But then your example with the Planck length falters, because it might be falsifiable in the future. Then we have an epistemological implosion: we don’t know what will be falsifiable and when, so the theory of meaning becomes vacuous.

The source of this issue is that claims that falsification is a very odd criterion of meaning, anyway. We should expect issues in that it appears one would have to understand the falsification criterion for the claim to be taken that way. Otherwise, people who are not familiar with the boundaries of current natural science will quantify over entities falsifiable and non-falsifiable–clearly, whichever they are makes little difference to them. But if they are indifferent to the distinction, then it seems like all of their statements are meaningless–the external criterion, completely apart from their linguistic practice, can’t distinguish them. So the odd result is that people who don’t understand the criterion simple speak nonsense. I think that consequence would invalidate the idea that falsification is a necessary condition for meaning.

I see the issue with falsifiability, and falsifiability ‘in principle’. It would be far to say, a certain sub-atomic particle’s existence is falsifiable in principle, if we have a microscope 100 times more powerful than anything now. But, if one were to say “X’s existence is falsifiable in principle, if we had a whole other set of senses, to perceive dimensions currently unknown to us”- it breaks down. Ultimately, anything may be said to be falsifiable in principle, IF we were omniscient!

Good point.

 

[Nihilist]

And how do you propose to prove that space and time exist?

Following Kant, the idea that they don’t actually exist, but are simply media of perception, they can be taken for granted as media, without positing their absolute existence. I don’t think they actually ‘exist’, except as media of perception.

 

[ynotzap]

Following Kant, the idea that they don’t actually exist, but are simply media of perception, they can be taken for granted as media, without positing their absolute existence. I don’t think they actually ‘exist’, except as media of perception.

Time is defined as change, that which changes is observable and known either in concrete objects that are sensed, or in concepts that are known. Change in external, concrete,physical objects is called locomotion, and change in concepts , going from not knowing ( having a capacity to know) to knowing (fufilling that capacity-Act) is called spiritual motion.
Leaving it to the media of conception is to making objective reality subjected to the mind, when in fact, it is the opposite, the mind to be in contact with reality has to be objective to the external objects, this contact comes initially through the senses from which we abstract our concepts.

 

[Oreoracle]

But, if one were to say “X’s existence is falsifiable in principle, if we had a whole other set of senses, to perceive dimensions currently unknown to us”- it breaks down. Ultimately, anything may be said to be falsifiable in principle, IF we were omniscient!

Falsifiability covers the potential for improved senses and technology. Again, Planck length serves as an example. You cannot observe a movement that is less than the Planck length no matter what technology or sensory perception you have. It’s a mathematical impossibility. If one couldn’t infer such movements indirectly, it would be unfalsifiable to say “X has moved a distance less than the Planck length”.

OK, but an ‘event’ in general occupy time, but not space.

The definition of “event” in physics is a point in spacetime; a set of 3 spatial coordinates and 1 time coordinate.

Take a sunrise. Now, the sun occupies space, but it is not the sunrise. The sunrise, as such, is not a physically locatable ‘thing’- it is rather it is a series of physical states, through time.

Yes, and the same is true of concerts. But it would seem perverse to argue that concerts do not have definite locations. Likewise, a sunrise happens on one side of the Earth at a given time but not the other. Also, they happen only on planets in our solar system. We may not mention the location in everyday conversation because it’s unnecessary, but there is certainly a (very large) location in mind.

Or perhaps saying ‘sunrise’ is just a manner of speaking, and all that really exists is the sun, moving through different states and locations?

Using the definition of “event” in physics, our colloquial usage of event would be a region of spacetime–a range of spatial and temporal coordinates that span a certain region.

This does not avoid the epistemological implosion I mentioned. We know what is observable according to our current technological capacities, but we do not know what is observable in principle.

I disagree. Again, I will cite the Planck length. Motion exceeding it is observable in principle, though perhaps not in practice. Motion that occurs within that range cannot be observed in principle if our physical theories are correct. It is mathematically impossible to do so.

(When you say “has no meaning,” what do you mean exactly?)

I mean that it is as meaningful as the statement “This statement is true.” The issue isn’t whether the statement is true or false, but rather the fact that it doesn’t seem to be asserting anything substantive. If you would prefer to call such statements “trivial” rather than meaningless, that’s fine.

I think most people would be willing to say that the leperchaun-postulator is wrong. (I think he is wrong. Maybe he’s right and we just can’t tell. But there is no need to introduce some “lack of meaning” that is clearly unrelated to the phenomenon of “meaning” in general.)

But on what grounds can he be wrong? As I said, meaningful, or non-trivial, statements imply that the observable world would be disturbed somehow if they were true. We then look for these disturbances and see if they match our expectations. The problem is that the claim of an ethereal being’s existence doesn’t imply any such disturbances, so we have nothing to check. The leprechaun doesn’t radiate heat, deflect light, block air currents, etc.

We may regard the leperchaun claim as nonsensical for a variety of reasons–for example, we think of leperchauns as bodily, visible beings that can make noises, so if we eliminate those essential features, we seem to be left with nothing, or something with features that contradict its essential features.

I agree entirely. This is very much how I feel when someone is arguing for God’s existence. They are asserting that something exists, but I’m not sure what disturbances I’m supposed to look for because God is described in an equally nebulous fashion. It’s an empty assertion, and that’s why there’s nothing to look for. Again, if you prefer to call that something other than “meaningless” then be my guest, but it seems meaningless/trivial/empty to me.

To go back to the relationship between falsifiability and meaning: I don’t think you’ve adequately addressed my points. For example, take a group of language-users who asserts things that are in principle falsifiable (assuming that this itself is unproblematic, which isn’t clear), but which they believe are unfalsifiable. They are therefore speaking nonsense.

Could you give an example? It should be evident whether or not something is falsifiable from the content of the claim.

 

[yppop]

Any argument about existence must be grounded in the indisputable observation that reality exists at four levels: objective, subjective, rational, and transcendental.

Objective reality consists of changes in the configuration: (1) of the electrons and quarks that exist as matter and is manifested as ponderable energy; (2) of space that is manifested as radiant energy. And that is about all that objective reality consists of.

Subjective reality consists of the qualia, feelings, and emotions that sentient creatures experience. Most of what we perceive and sense exists within our minds. All creatures experience, at the minimum, a semblance of subjective reality.

Rational reality consists of the signals and symbols, and solely in the case of humans: words, thoughts, numbers, logic, and language and their associated meanings. Unlike subjective reality, rational reality is communicative and forms a repository of shared knowledge, a so-called noosphere.

Transcendental reality consists of those intellectual sensations such as justice, beauty, love, and truth that only humans experience.

Yppop

 

[polytropos]

I disagree. Again, I will cite the Planck length. Motion exceeding it is observable in principle, though perhaps not in practice. Motion that occurs within that range cannot be observed in principle if our physical theories are correct. It is mathematically impossible to do so.

And our basis for holding such theories has changed over time; there was a point in the past when no one had an understanding of the Planck length. Were their claims about motion exceeding the Planck length meaningful or meaningless then? (Were they made meaningful by future scientific discoveries?)

I mean that it is as meaningful as the statement “This statement is true.”

Well, that doesn’t help much. What is the semantic similarity between nonfalsifiable and self-referential propositions? There doesn’t seem to be any.

The issue isn’t whether the statement is true or false, but rather the fact that it doesn’t seem to be asserting anything substantive. If you would prefer to call such statements “trivial” rather than meaningless, that’s fine.

But on what grounds can he be wrong? As I said, meaningful, or non-trivial, statements imply that the observable world would be disturbed somehow if they were true. We then look for these disturbances and see if they match our expectations. The problem is that the claim of an ethereal being’s existence doesn’t imply any such disturbances, so we have nothing to check. The leprechaun doesn’t radiate heat, deflect light, block air currents, etc.

I would reserve “trivial” for its mathematical usage. I don’t know how nonfalsifiable claims could be taken to assert nothing substantive as any sort of general rule. Suppose someone says, “There is an invisible dragon in my garage.” Well, clearly, “There is an invisible dragon in my garage or there is not an invisible dragon in my garage.” Someone who asserts such a statement is simply grasping a particular prong of that “dilemma.” I can understand what he means–even if I disagree with him–simply because I can understand the analogous statement, “There is a lawn mower in my garage.”

In general, I don’t need “disturbances” or consequences or implications to understand someone’s utterance. If someone were to tell me, “Your great grandmother has a spoon collection, but it was incinerated and there are no records,” I can’t necessarily prove that statement true or false. (I may even believe it, depending on the authority of who tells me.) It doesn’t really make a difference to me today. The statement is hardly trivial, bereft of content, “not even wrong,” or what have you simply because it isn’t a scientifically testable hypothesis. (It seems to me like any disanalogies between the case of no longer falsifiable claims about the past and ridiculous unfalsifiable hypotheses today would not be relevant. Maybe you’d disagree.)

I agree entirely. This is very much how I feel when someone is arguing for God’s existence. They are asserting that something exists, but I’m not sure what disturbances I’m supposed to look for because God is described in an equally nebulous fashion. It’s an empty assertion, and that’s why there’s nothing to look for. Again, if you prefer to call that something other than “meaningless” then be my guest, but it seems meaningless/trivial/empty to me.

But I wasn’t saying that the leperchauns are described “nebulously” (I take that to mean vaguely, or nonspecifically), but that an invisible, mute leperchaun possesses attributes that directly contradict other attributes of leperchauns. This isn’t analogous to a lack of “disturbances.”

For example, I would be sympathetic to an argument for the leperchaun if people argued: this is what exists, and if this is what exists, then there must be a being of this sort, and a being of this sort happens to possess attributes that we commonly associate with leperchauns. I doubt anyone would manage to create a plausible argument to that effect, but I would listen to it and be able to express where I disagree. Arguments for God similarly (tend to) argue from the world to God as a necessary condition of its possibility. They do not tend to be god-of-the-gaps argument that pick out a particular phenomenon (a “disturbance”) and propose that we explain that phenomenon with God, or that we invoke God in order to predict future occurrences of that phenomenon. To read assertions about God’s existence in that way is simply to misunderstand them.

Could you give an example? It should be evident whether or not something is falsifiable from the content of the claim.

No it’s not. Judging a claim as falsifiable or not requires background knowledge (ie. of the Planck length). A group of people may be in possession of a deficient scientific theory that states that the length under which observation is in principle impossible is greater than the Planck length. So then they make assertions about motions that are smaller than their length, but greater than the Planck length. Their claims are in principle falsifiable, but they believe they are unfalsifiable. It strains credulity to say that whether or not their claims “mean” anything has to do with some scientific theory they haven’t figured out yet.

 

[Oreoracle]

And our basis for holding such theories has changed over time; there was a point in the past when no one had an understanding of the Planck length. Were their claims about motion exceeding the Planck length meaningful or meaningless then? (Were they made meaningful by future scientific discoveries?)

No one could make a claim of the form “this object is moving within the Planck length” before the notion of “Planck length” existed.

I know what you’re getting at though. You’re asking about an assertion such as “this object has moved a very small distance” and then we find out later that that distance was within the Planck length. Let’s say that the original claim was made within a Newtonian understanding of physics. Such a claim is falsifiable within the Newtonian framework because classical mechanics assumes continuity of space and offers no restrictions on the potential for measurement.

I should have been clearer on this. I take “falsifiability” to mean “falsifiable within the context of the theory in question”. I don’t intend to use it in some absolute sense. So the issue with the leprechaun should be clear now: It postulates something that is unfalsifiable in the context of our current understanding of physics. Perhaps our understanding of what is observable is not yet complete, but as you said, intention determines meaning. Someone who defines something so as to be undetectable within our current theories cannot be asserting that that thing corresponds to reality in any tangible sense. The statement may be understood by someone in the future under a different theory, but it is meaningless within the vocabulary of the current theory.

Can we agree on that much?