Evolution as a "fact"

[Aelyn]

Greetings,
You're welcome!

Just reading through Why don't you believe the bible?

Kindest regards,

James

I've still got a half-finished reply for that thread lying around... But the guy I was talking with in it isn't around a lot now so it remains unposted. And the OP never replied to me so I think it's likely he isn't really that interested anymore.

 

[Inferno]

Which topics are you in?

This one and this one.

 

[Dragan Glas]

Greetings,

Greetings,
You're welcome!

Just reading through Why don't you believe the bible?

Kindest regards,

James

I've still got a half-finished reply for that thread lying around... But the guy I was talking with in it isn't around a lot now so it remains unposted. And the OP never replied to me so I think it's likely he isn't really that interested anymore.

I noticed that TeeJay kept saying that atheists can't use the "immaterial" laws of logic to disprove God.

He's conflating - I won't say "equivocating"(!) - "immaterial" with "supernatural": YesYouNeedJesus did something similar in another topic here - there was another example of it here - both of which I addressed.

As I explained it, naturalistic phenomena - such as the force of gravity and magnetic lines of force, for example - are "immaterial" (non-physical) but have a wholly naturalistic (physical) cause: not supernatural.

Kindest regards,

James

 

[Aelyn]

I noticed that TeeJay kept saying that atheists can't use the "immaterial" laws of logic to disprove God.

He's conflating - I won't say "equivocating"(!) - "immaterial" with "supernatural": YesYouNeedJesus did something similar in another topic here - there was another example of it here - both of which I addressed.

As I explained it, naturalistic phenomena - such as the force of gravity and magnetic lines of force, for example - are "immaterial" (non-physical) but have a wholly naturalistic (physical) cause: not supernatural.

Kindest regards,

James

I think you're right. Though I personally wouldn't call the force of gravity and magnetic lines immaterial either - I'd say they're the way massive and charged particles move, and if something is material I don't see why I'd call its characteristics or behavior immaterial, other than as a quibble on semantics.

I actually tried to start another thread in the "Miscellaneous" forum to sort out what people actually meant by those words but it didn't go very far. If Teejay shows up again I might ask him about it.

 

[Dragan Glas]

Greetings,

I think you're right. Though I personally wouldn't call the force of gravity and magnetic lines immaterial either - I'd say they're the way massive and charged particles move, and if something is material I don't see why I'd call its characteristics or behavior immaterial, other than as a quibble on semantics.

I actually tried to start another thread in the "Miscellaneous" forum to sort out what people actually meant by those words but it didn't go very far. If Teejay shows up again I might ask him about it.

One could argue that magnetism is "the way [..] charged particles move" - but they do so due to "immaterial" magnetic lines of force. Similarly, "immaterial" gravitational lines of force cause massive bodies to move. Both "lines of force" are due to physical phenomena.

Regardless, the point I was making - in the linked posts and in my reply to you, Aelyn - was that they (Creationists) tend to confuse "immaterial/non-physical" with "spiritual/supernatural", rather than phenomena which are or have a purely physical/naturalistic explanation: such as the "mind" (ergo "soul") being the result of biochemical processes of the brain.

The meanings of words is another point of contention - again various Creationists use the terms "micro-evolution" and "macro-evolution" in a different way than do scientists, which makes discussing these concepts nigh impossible.

Kindest regards,

James

 

[Inferno]

I love it. I gave them the chance to tell me what a macroevolution is and *SNAP*, they've fallen into the trap. Gilbo called something a macroevolutionary event even though it has already been found, he called something "hypothetical" even though it's already been found and he even defined information. This last one deserves a bit of an explanation: I proposed the "what if" version of a gene or a sequence of DNA being lost to produce a beneficial change. He said that was a loss of information. Then I said what if a gene or sequence of DNA was added to produce a beneficial change. He immediately backtracked and said "that would still be a microevolutionary event".

Yes, but now put the two together! We've got a macroevolutionary event even by your definition and we've got an increase of information even by your definition. Now put the two together.

I'll post the references and explanations on their forum when I get home. I've had a lot of fun, but after that I'm done there.

 

[Frenger]

That's awesome Inferno. I'm excited to see, despite all your work Gilbo STILL claiming it doesn't happen. I can't access the site from work but will be sure to have a look when I get home.

 

[Aelyn]

Greetings,

One could argue that magnetism is "the way [..] charged particles move" - but they do so due to "immaterial" magnetic lines of force. Similarly, "immaterial" gravitational lines of force cause massive bodies to move. Both "lines of force" are due to physical phenomena.

What do you mean, "lines of force cause things to move" ? There is no evidence for such lines of force other than the movements we observe, which means saying those lines of force cause things to move is an empty statement. And in the case of gravity it's actually a false statement, since it's not "lines of force" that cause massive objects to move the way they do, it's the curvature of spacetime. And other forces are mediated by bosons though that's about as much as I know about that.

"Lines of force" are an abstraction, a metaphor we use to understand how magnetic and gravitational forces work, they're not something that actually exists as far as I know. When you draw your magnetic lines of force on a figure what you're actually saying is that in those points, the vectors of electric and magnetic force are in this direction and have that magnitude. And that's the same thing as saying that if you put a charged particle at this point it would undergo this acceleration.

Regardless, the point I was making - in the linked posts and in my reply to you, Aelyn - was that they (Creationists) tend to confuse "immaterial/non-physical" with "spiritual/supernatural", rather than phenomena which are or have a purely physical/naturalistic explanation: such as the "mind" (ergo "soul") being the result of biochemical processes of the brain.

Yes, as I said I agree with you on that. Even if we did agree on the definition of material and immaterial they're still making assumptions on how those two things can and can't interact.

 

[Dragan Glas]

Greetings,

Greetings,

One could argue that magnetism is "the way [..] charged particles move" - but they do so due to "immaterial" magnetic lines of force. Similarly, "immaterial" gravitational lines of force cause massive bodies to move. Both "lines of force" are due to physical phenomena.

What do you mean, "lines of force cause things to move" ? There is no evidence for such lines of force other than the movements we observe, which means saying those lines of force cause things to move is an empty statement.

They are representative of the magnetic field around a bar magnet, for example. Perhaps if I'd said "magnetic field" instead of "lines of force" it would have been better stated.

Said magnetic "lines of force" - as evidenced by iron filings in a bar magnet's magnetic field, for example - represent cross-sections of the magnetic "shells", in which such filings are held.

And in the case of gravity it's actually a false statement, since it's not "lines of force" that cause massive objects to move the way they do, it's the curvature of spacetime. And other forces are mediated by bosons though that's about as much as I know about that.

I was getting tired as I was posting this and repeated myself - perhaps I should have used "gravitational field", similar to the above.

"Lines of force" are an abstraction, a metaphor we use to understand how magnetic and gravitational forces work, they're not something that actually exists as far as I know. When you draw your magnetic lines of force on a figure what you're actually saying is that in those points, the vectors of electric and magnetic force are in this direction and have that magnitude. And that's the same thing as saying that if you put a charged particle at this point it would undergo this acceleration.

To my knowledge the "shells" of a magnetic field are actual - they are only found at specific distances from the magnet, and there are more or fewer such "shells" depending on whether the strength of the field increases or decreases, respectively.

I would, of course, bow to a physicist's expertise at this point... :mrgreen:

Regardless, the point I was making - in the linked posts and in my reply to you, Aelyn - was that they (Creationists) tend to confuse "immaterial/non-physical" with "spiritual/supernatural", rather than phenomena which are or have a purely physical/naturalistic explanation: such as the "mind" (ergo "soul") being the result of biochemical processes of the brain.

Yes, as I said I agree with you on that. Even if we did agree on the definition of material and immaterial they're still making assumptions on how those two things can and can't interact.

I'm glad I got something right!

In view of our above disagreement, I'd suggest using the term "magnetic/gravitational field" when bringing up the point about conflating "immaterial" with "supernatural" - it would give Creationists little or no grounds to argue.

Kindest regards,

James

 

[Aelyn]

Greetings,

They are representative of the magnetic field around a bar magnet, for example. Perhaps if I'd said "magnetic field" instead of "lines of force" it would have been better stated.

Said magnetic "lines of force" - as evidenced by iron filings in a bar magnet's magnetic field, for example - represent cross-sections of the magnetic "shells", in which such filings are held.

(...)
I was getting tired as I was posting this and repeated myself - perhaps I should have used "gravitational field", similar to the above.

But what's a "gravitational field" ? It just means "places that experience a gravitational force". The actual causes of that force are spacetime curvature (in a relativistic context), gravitons (in quantum gravity, maybe, honestly I don't see how that's consistent with relativity at all), or unkown (in Newtonian mechanics).

When you say "massive objects create a gravitational field that induces acceleration in other massive objects" vs "massive objects induce acceleration in other massive objects", what additional information does the "gravitational field" formulation add ? Whereas in "massive objects warp spacetime which induces apparent acceleration in other massive objects", the whole "warp spacetime" bit is a substantive addition that makes certain predictions and not others.

To my knowledge the "shells" of a magnetic field are actual - they are only found at specific distances from the magnet, and there are more or fewer such "shells" depending on whether the strength of the field increases or decreases, respectively.

I would, of course, bow to a physicist's expertise at this point... :mrgreen:

I'm not a physicist, but I still disagree... It's like saying that ocean waves are immaterial or have an existence independent of the water they're in. It's a very good way of conceptualizing how oceans work, but while you might say waves cause a boat to go up and down that doesn't mean there's an immaterial "wave" that's causing the motion independently of the water; the wave is a description of the water's motion and the water is what's moving the boat.
And I don't know what you mean when you say "shells" of magnetic field are only found at specific distances from the magnet. IIRC there's an infinity of "shells" that exist at every distance from the magnet; it's their density that varies and determines the strength of the field. IOW they're a way of picturing how the strength of the field is distributed.

In view of our above disagreement, I'd suggest using the term "magnetic/gravitational field" when bringing up the point about conflating "immaterial" with "supernatural" - it would give Creationists little or no grounds to argue.

Nah, they'll just say that proves their point that God is responsible for magnetic fields

 

[CosmicJoghurt]

I'm reading through the thread on EvolutionFairyTale, and I can see why Gilbo has pretty much abandoned LoR. Everyone there seems to agree with his ignorant crap.

Though, I did register for the forum 3 days ago. Don't know why but it hasn't been approved.

I just obseved last night that you are a 22 yr old atheist. That explains it.

Whether you like it or not ALL living organisms bring forth offspring after their kind/type. You will never observe anything else...ever.

Yes, that's the sort of stuff you see there.

 

[he_who_is_nobody]

Sorry for the delay in this, but I have limited Ethernet access and it is Christmas. I just wanted to point out a mistake everyone seems to be making when it comes to gilbo12345 use of the phrase "plasticity in science". Gilbo12345 is correct to point out that science is ever changing when new facts and evidence is presented. However, the mistake gilbo12345 is making is not with the definition of "fact" and "scientific fact", but in his equivocation of "evolution" and "evolutionary theory"., 

Hen biologist say evolution is a fact, they almost undoubtedly mean evolution (change on allelic frequencies in a population over time). This is a fact by both the laypersons use of fact w d the scientific use if fact (this was also explained to him on the first page of this thread). If tomorrow someone were to refute universal common descent, the age of the earth, or anything else that is a part of the theory of evolution, it would do nothing to change the fact that we have observed genes change in a population over time (i.e. Evolution). Whatever theory came to replace evolutionary theory would still have to incorporate that observation., 

As I have already pointed out, semantics is the last bastion for creationist argumentation, without it, gilbo12345 would have to argue the science. Gilbo12345, in my opinion, was successful in this tactic as well, because gilbo12345 was able to equivocate several different terms and turn this whole thread into one big argument about definitions of words instead of arguing against evolutionary theory. , 

 

[Gnug215]

Sorry for the delay in this, but I have limited Ethernet access and it is Christmas. I just wanted to point out a mistake everyone seems to be making when it comes to gilbo12345 use of the phrase "plasticity in science". Gilbo12345 is correct to point out that science is ever changing when new facts and evidence is presented. However, the mistake gilbo12345 is making is not with the definition of "fact" and "scientific fact", but in his equivocation of "evolution" and "evolutionary theory"., 

Hen biologist say evolution is a fact, they almost undoubtedly mean evolution (change on allelic frequencies in a population over time). This is a fact by both the laypersons use of fact w d the scientific use if fact (this was also explained to him on the first page of this thread). If tomorrow someone were to refute universal common descent, the age of the earth, or anything else that is a part of the theory of evolution, it would do nothing to change the fact that we have observed genes change in a population over time (i.e. Evolution). Whatever theory came to replace evolutionary theory would still have to incorporate that observation., 

As I have already pointed out, semantics is the last bastion for creationist argumentation, without it, gilbo12345 would have to argue the science. Gilbo12345, in my opinion, was successful in this tactic as well, because gilbo12345 was able to equivocate several different terms and turn this whole thread into one big argument about definitions of words instead of arguing against evolutionary theory. , 

I knew this was what he was doing (the equivocation thing), and basically yelled it at him, but well, he didn't seem to understand my first few posts, and my most recent one (with big green letters) has not been responded to.

 

[Dragan Glas]

Greetings,

I'm reading through the thread on EvolutionFairyTale, and I can see why Gilbo has pretty much abandoned LoR. Everyone there seems to agree with his ignorant crap.

Though, I did register for the forum 3 days ago. Don't know why but it hasn't been approved.

I just obseved last night that you are a 22 yr old atheist. That explains it.

Whether you like it or not ALL living organisms bring forth offspring after their kind/type. You will never observe anything else...ever.

Yes, that's the sort of stuff you see there.

I've had something of a similar experience.

I'd registered just before Christmas and, whilst perusing a topic, my name appeared as a live-link at the bottom of the page. When I clicked on it, I got a message to the effect that I couldn't view members' profiles - I then attempted to log in but was then told there was a error (presumably my profile didn't exist yet until approved?!). Meanwhile, the live-link on the thread disappeared when I refreshed the page.

So, I've registered again and await developments.

Kindest regards,

James

 

[Dragan Glas]

Greetings,

Greetings,

They are representative of the magnetic field around a bar magnet, for example. Perhaps if I'd said "magnetic field" instead of "lines of force" it would have been better stated.

Said magnetic "lines of force" - as evidenced by iron filings in a bar magnet's magnetic field, for example - represent cross-sections of the magnetic "shells", in which such filings are held.

(...)
I was getting tired as I was posting this and repeated myself - perhaps I should have used "gravitational field", similar to the above.

But what's a "gravitational field" ? It just means "places that experience a gravitational force". The actual causes of that force are spacetime curvature (in a relativistic context), gravitons (in quantum gravity, maybe, honestly I don't see how that's consistent with relativity at all), or unkown (in Newtonian mechanics).

When you say "massive objects create a gravitational field that induces acceleration in other massive objects" vs "massive objects induce acceleration in other massive objects", what additional information does the "gravitational field" formulation add ? Whereas in "massive objects warp spacetime which induces apparent acceleration in other massive objects", the whole "warp spacetime" bit is a substantive addition that makes certain predictions and not others.

Perhaps, but one then comes back to the question of what "warps" space-time? Gravity (or the gravitational field/force of a massive body).

To my knowledge the "shells" of a magnetic field are actual - they are only found at specific distances from the magnet, and there are more or fewer such "shells" depending on whether the strength of the field increases or decreases, respectively.

I would, of course, bow to a physicist's expertise at this point... :mrgreen:

I'm not a physicist, but I still disagree... It's like saying that ocean waves are immaterial or have an existence independent of the water they're in. It's a very good way of conceptualizing how oceans work, but while you might say waves cause a boat to go up and down that doesn't mean there's an immaterial "wave" that's causing the motion independently of the water; the wave is a description of the water's motion and the water is what's moving the boat.
And I don't know what you mean when you say "shells" of magnetic field are only found at specific distances from the magnet. IIRC there's an infinity of "shells" that exist at every distance from the magnet; it's their density that varies and determines the strength of the field. IOW they're a way of picturing how the strength of the field is distributed.

I understand what you're saying regarding waves moving a boat up and down, though the waves are caused by something else which is immaterial - whether tides being caused by the Moon's gravity, waves being caused by wind (I know - the atmosphere is itself material and "wind" is just the movement of air...).

I've always viewed the "shells" (denser field strength) as akin to electron shells in a atom - hence my use of the term.

In view of our above disagreement, I'd suggest using the term "magnetic/gravitational field" when bringing up the point about conflating "immaterial" with "supernatural" - it would give Creationists little or no grounds to argue.

Nah, they'll just say that proves their point that God is responsible for magnetic fields

O-kay :roll: ( ) ... perhaps just saying "gravity/magnetism"?! ... would that suffice??! :lol:

Kindest regards,

James

 

[Aelyn]

Greetings,

Perhaps, but one then comes back to the question of what "warps" space-time? Gravity (or the gravitational field/force of a massive body).

That's a tautology. What causes gravity ? Warps in space-time. What causes warps in space-time ? Gravity. Tautologies are worse than useless because they're a way of saying nothing while pretending you did say something.
The actual answer to that question AFAIK (which in this case may not be as much as science knows) is the same answer that Newton gave when asked why gravity caused masses to attract, i.e. "I don't know".
All scientific theories eventually hit "I don't know", it's not a flaw. In this case the difference between Newtonian and Relativistic gravity is that the latter has an extra non-empty explanatory step before you get to "I don't know".

Do you understand how "space is warped" is substantive in a way "there's a gravitational field" is not ? I'm not completely sure how to explain but I can try if you like (and if I start doing so and find out I was wrong all along in the process, well there we'll be).

I understand what you're saying regarding waves moving a boat up and down, though the waves are caused by something else which is immaterial - whether tides being caused by the Moon's gravity, waves being caused by wind (I know - the atmosphere is itself material and "wind" is just the movement of air...).

You're seeing where I come from

I've always viewed the "shells" (denser field strength) as akin to electron shells in a atom - hence my use of the term.

In that case I think you might just be wrong on how magnetism works, though of course it's been a long time for me too so it could just be the other way around... I see two issues with the concept of actual, discrete, localized shells. First, does that mean that there is no electromagnetic force between two shells ? (and given that the density of electromagnetic force is related to the number of shells there are that means there can be any distance between two shells, given a weak enough electromagnetic force. Would that be right ?). And second, doesn't that suggest a maximum number of shells that can fit in a given area ?

I tried to google "magnetic shells" but couldn't find much.

 

[Dragan Glas]

Greetings,

Greetings,

Perhaps, but one then comes back to the question of what "warps" space-time? Gravity (or the gravitational field/force of a massive body).

That's a tautology. What causes gravity ? Warps in space-time. What causes warps in space-time ? Gravity. Tautologies are worse than useless because they're a way of saying nothing while pretending you did say something.
The actual answer to that question AFAIK (which in this case may not be as much as science knows) is the same answer that Newton gave when asked why gravity caused masses to attract, i.e. "I don't know".
All scientific theories eventually hit "I don't know", it's not a flaw. In this case the difference between Newtonian and Relativistic gravity is that the latter has an extra non-empty explanatory step before you get to "I don't know".

Do you understand how "space is warped" is substantive in a way "there's a gravitational field" is not ? I'm not completely sure how to explain but I can try if you like (and if I start doing so and find out I was wrong all along in the process, well there we'll be).

Hmm, well I'd have said that massive bodies cause gravity - but I see what you're saying about it depending on which physics one is using - Newtonian, Einsteinian, etc.

I understand what you're saying regarding waves moving a boat up and down, though the waves are caused by something else which is immaterial - whether tides being caused by the Moon's gravity, waves being caused by wind (I know - the atmosphere is itself material and "wind" is just the movement of air...).

You're seeing where I come from

Yes indeed.

I've always viewed the "shells" (denser field strength) as akin to electron shells in a atom - hence my use of the term.

In that case I think you might just be wrong on how magnetism works, though of course it's been a long time for me too so it could just be the other way around... I see two issues with the concept of actual, discrete, localized shells. First, does that mean that there is no electromagnetic force between two shells ? (and given that the density of electromagnetic force is related to the number of shells there are that means there can be any distance between two shells, given a weak enough electromagnetic force. Would that be right ?). And second, doesn't that suggest a maximum number of shells that can fit in a given area ?

I tried to google "magnetic shells" but couldn't find much.

I have to concede that my conception of magnetic lines/shells were from a remembered physics class many, many years ago, where the physics teacher used a bar magnet with iron filings to demonstrate the magnetic field.

As I recall, the filings formed distinct lines - with very few filings in-between.

However, having found an article with a picture of a similar experiment, it's clear that the above impression was caused by too few filings.

Point to Aelyn.

*sobs* :lol:

Kindest regards,

James

 

[CommonEnlightenment]

Huh..... What?

It appears a minor review of the principle of equivalence may be in order.

Are we talking about spooky action at a distance here?

 

[Aelyn]

Huh..... What?

It appears a minor review of the principle of equivalence may be in order.

Are we talking about spooky action at a distance here?

I don't know, who are you talking about and what do you think they're saying ?

 

[Aelyn]

Hmm, well I'd have said that massive bodies cause gravity - but I see what you're saying about it depending on which physics one is using - Newtonian, Einsteinian, etc.

I'm not sure what you mean by that, and re-reading your previous reply I'm not sure I'd completely understood that one either; I'd assumed you were using "gravity" as an empty label when you said gravity warps spacetime but now I wonder whether you were misunderstanding the theory of relativity. To cover the bases I'll explain the theories of gravity as I understand them, and at the same time try that explanation of why one hypothesis is more substantive than another that I wasn't sure how to do earlier.

To get back to basics, the phenomenon we have is that certain objects move in certain ways - planets orbit in ellipses around the Sun, apples fall onto the Earth, etc. Newton found that if we assumed all massive objects exerted a force on each other proportional to their mass and inversely proportional to the square of the distance between them, such a force would account for all those different movements - that force was called "gravity".

All we know in this context is that massive objects exert this force on each other - we don't know why, or how (in fact IIRC it was a complete coincidence in Newtonian terms that gravitational mass was the same as inertial mass, i.e. that the "m" in F=Gmm'/R2 was the same "m" as in F=ma). If we try to "explain" this by saying that massive objects induce an immaterial gravitational field that causes the movement of far-away objects to be affected, for this explanation to be in any way distinguishable from just "massive objects affect the movement of other massive objects" (or "massive object spookily act on other massive objects at a distance") you'd need some indication this gravitational field exists independently from the movements it induces (otherwise you might as well just have the movements). In other words, does the gravitational field of the Sun exist in places where there is no massive object to be affected by it ? Presumably otherwise what's the point, but if the gravitational field is defined only and exclusively by how it affects massive objects, then there is literally no way to find out. Gravitational fields can be a useful mathematical or conceptual tool, but as long as they're mathematically equivalent to there not being a gravitational field that's all they can be : a mathematical tool.

Now in the Theory of Relativity gravity doesn't exist as a force. Massive objects cause spacetime to curve, not because of the force of gravity attracting spacetime or something like that. The often-used analogy of bowling balls on a rubber surface also has the often-used caveat that bowling balls actually curve rubber surfaces (and little balls roll around that curve) because they're attracted by the Earth's gravity, whereas what makes spacetime curve around massive objects is not the same thing at all. AFAIK we don't know what it is, unless the Higgs condensate has something to do with it.
According to the Theory of Relativity, gravity is actually a pseudo-force, like the "force" that pushes you back on an accelerating car or train or the centrifugal "force" that pushes spinning things outward. Those aren't actually forces, the movements involved are just objects moving inertially in a non-inertial frame of reference, so that within that frame of reference it looks like a force is acting on them, when actually it's the frame of reference that's accelerating and either pulling them along or leaving them standing so that they look like they're accelerating backwards. Same thing with orbiting planets or falling apples : they're inertially taking the shortest route from point A to point B through curved space, which if you assume space is flat makes it look like a force is causing their trajectory to curve.

So now we've got "massive objects cause warped space which affects the movements of other massive objects"; is "warped space" an empty hypothesis like I say "gravitational field" is ? Well, if we ask the same questions of it that I asked for the gravitational field the answers are more clear - is space near the Sun warped even in points where there isn't a massive object there to be affected by it ? - Yes, the statement "massive objects warp spacetime" clearly doesn't depend on their being another massive object at that point in space. Would this have other effects beyond F=Gmm'/R2 ? Yes - warps in spacetime won't just affect massive objects, we'd expect to see effects on light or on passing time and other elements of the Universe beyond just mass. Even if there weren't any effects we could check in practice, the equations involved in the Theory of Relativity are different from those involved in Newtonian gravity so mathematically speaking there is a difference between a world where curved space causes apples to fall and one where immaterial fields, or spooky action at a distance, or anything else causes it.

To get back to your answer, massive bodies "cause gravity" whichever theory you pick; the question is how they "cause gravity", and which ways of conceptualizing this process are actual hypotheses about the world and which are conceptual tools.

I have to concede that my conception of magnetic lines/shells were from a remembered physics class many, many years ago, where the physics teacher used a bar magnet with iron filings to demonstrate the magnetic field.

As I recall, the filings formed distinct lines - with very few filings in-between.

However, having found an article with a picture of a similar experiment, it's clear that the above impression was caused by too few filings.

That's interesting. I did study physics beyond the iron fillings bit (I probably have something not too far from a bachelor's), and it was clear the separate lines were conceptual; the equation defining what the magnetic force was at any point worked for any non-zero point, i.e. the force existed everywhere outside of the magnet. We even had to draw those lines sometimes; IIRC (and I very well might not) they're the equivalent of the lines on a topographical map : they indicate all the points that are at the same level, but they're not the only such lines that exist, only those you chose to draw. (the reason I have a problem with the topographical map analogy is that there is a directionality involved in magnetic fields and that's actually what the lines show; hence why iron fillings illustrate them nicely, because they tilt themselves to align with what that direction is wherever they happen to be. The equivalent drawing for an electric field or a (Newtonian) gravitational field would be lines radiating straight outwards)