Reflections on dying

My father died last week.  I am now the sole surviving member of my immediate family.  My sister died in 2020 and my mother in 2024.  The experience of dealing with three deaths in the family has been... interesting.  There are things I know now that I wish I'd known then, and things I can reveal now that I could not before.  I'm writing this in the hope that someone reading this may end up better prepared than I was, and may even be able to save someone.  Because my sister died in 2020, everyone assumes it was due to covid, and in a way it was, but covid is not what killed her.  She died from anorexia.  And, as it turns out, it goes all the way back to when she was in junior high school.  I know this from a letter that she wrote back then, which I discovered among my parent's effects after my father died.

The entire time we were living together in my parents' house, and even well after we both left to go to college, I had no clue there was anything wrong.  My sister looked healthy, seemed healthy.  She was enormously popular among her peers.  She was literally the homecoming queen in high school.  Among my parent's effects I found a plaque naming her "friendliest person" in her class.  But even then she was already, ever so slowly, killing herself.

She hid her disease exceptionally well.  Throughout her twenties and thirties she looked extraordinarily healthy.  At one point she got into body-building.  She looked like this:

 

Twenty years later she looked like this:

 

That is a photo of her with my father on a trip to Disney World in 2019.  She was 53 years old.   We didn't know it at the time, but that would be our last time together as a family.  Nine months after that photo was taken the covid lockdown began, and five months after that she would be found dead in her condo.  If the pandemic had not happened it's possible she would have been in the office that day, but instead she was working from home where she lived by herself with her two cats.

I debated with myself for a long time over whether to publish that photograph.  I don't want her to be remembered that way.  I want her to be remembered the way she was in her prime.  But even in her prime she was already sick, and so I decided to show what she looked like at the end in the hopes that others might be able to avoid her fate.  One of the insidious things about anorexia is how slowly it kills.  Irit appeared to be fine for decades.   But she obviously wasn't fine.  By the time it became evident that she wasn't fine, it was probably too late to do anything.  When we saw her in 2019 everyone in the family was shocked.  She had been getting thinner for a very long time, but now she looked like she'd walked out of a Nazi concentration camp.  Moved by her shocking extreme gauntness, everyone in the family tried to talk to her, to tell her that she needed to eat more, but it was far, far too late.  We didn't know it, but she was already walking dead, and had been for a very long time.

My sister's disease was born when she was still a teenager.  And one of its roots is something that I could never publicly reveal while my father was still alive.  I don't think he ever realized this, and if he had, I think it would have destroyed him.  You see, when we were children, my father had a pet name for my sister.  He called her, in Hebrew, "shmeine-bumba" which, roughly translated, means "little chubby one."

Of course, she wasn't.  My sister was never chubby.  But that was the self-image that my father's pet name seared onto her soul.

[Interlude] 

I've been staring at the above paragraph for three days now wondering how to finish this post.  I want this story to somehow be constructive, to be a call to action, but the problem is I'm not sure what kind of action to call for.  My wife correctly predicted that my sister was going to die years before she actually did, and wanted to intervene somehow, but even today I don't know what a successful intervention would or even could have looked like.  The problem is that by the time it was evident from looking at her that she had a problem it was probably already too late.  Many people tried to tell her that she was too thin, but she refused to talk about it.  Short of strapping her to a gurney and force-feeding her, I don't know what could have been done.

Normally my advice in a situation like this would be to consult an expert.  But the irony is that my sister was an expert.   She was a psychology professor.  She had a Ph.D.  She actually worked as a consultant counseling obese people before getting gastric bypass surgery.

So I guess my hope here is just to raise awareness.  Be aware, and be kind.  Don't tease your daughters about being fat.  If you are a young person, don't tease your peers about being fat (especially if they aren't) either on-line or IRL.   You could, quite literally, be killing them.

Slowly.

Very,

very,

slowly.

[UPDATE] My wife pointed me to this article, which is based on this research paper.

This quote from the article really struck me:

Up to one in five people with chronic anorexia may die as a result of their illness, either due to the direct effects of starvation and malnutrition or due to suicide, making it the deadliest of all psychiatric disorders.

 Yep.

Seeking God in Science part 4: Chairness

I concluded the last installment in this series with a deceptively simple claim: Things exist.  This two-word quip is a scientific hypothesis, an explanation for some of my subjective experiences, specifically, my ability to see and touch and hear and small and taste, well, things.  The explanation is that these things that I perceive really do exist in point of actual physical (and possibly metaphysical) fact, i.e. that there is an objective reality that actually exists "out there", independent of my mind.  This is so obviously true, so obviously the correct explanation that there seems at first glance to be no point in discussing it at all.  But as we will see, this hypothesis actually turns out to have some pretty serious problems, and in fact, when we drill down far enough, it will actually turn out to be wrong.

But let's take this one step at a time.

First, let's give this hypothesis a name.  I'm going to call it the Objective Reality hypothesis, or ORH for short.  This hypothesis says that some (though not necessarily all) of my subjective perceptions can be accounted for in a totally straightforward way by the existence of actual physical things.  I can see and touch and hear other people because there actually are other people, and we can all agree that there are chairs and tables and computers because there actually are chairs and tables and computers.

At this point you may be thinking, well duh, of course the reason everyone agrees there are chairs is because there really are chairs.  But it's not so simple.  Consider, for example, rainbows.  People will agree that they see a rainbow just like they agree that they see a chair, but a rainbow is unlike a chair in some fundamental ways.  You can see a rainbow, but you can't touch it.  If you try to get close enough to a rainbow to touch it, the rainbow will disappear.  Rainbows are part of objective reality but they are not physical things.  Rainbows are just water droplets lit up in a very particular way.

Rainbows are not the only things that look like they might be physical objects but actually aren't.  You are probably reading this on a computer screen, which can mimic the visual appearance of just about anything.  Before computer screens there were movies, and before movies there were paintings, and after computer screens there will probably be virtual reality glasses or implants.  As technology improves, it gets harder and harder to distinguish actual physical reality from a simulation.

Aside: a while ago I got a demo of the Apple Vision Pro, which is a virtual reality headset.  While you are wearing it what you are actually looking at is a pair of tiny screens.  But there is also a camera which projects an image of whatever the headset is pointed at onto the screens.  The illusion is so compelling that during the demo I actually forgot that I was looking at a screen and became convinced that the screens were transparent, that I was actually looking through them and directly seeing the room I was in.

Which brings up an interesting question: how can you be sure that the things you perceive as actual physical objects are in fact actual physical objects and not a simulation?  How can you tell the difference between "real" objective reality and a high-quality virtual reality, one that includes all of your sensory modalities?  How can you be sure that reality is actually real and you are not just living in The Matrix?

I'll leave that as an exercise for now and proceed on the assumption that objective reality is actually real, and that part of this objective reality consists of real physical objects like chairs.  I'm going to refer to such objects as Things with a capital T.  Objective reality includes abstract things like words and ideas and sounds, and ephemeral things like rainbows and the images on computer screens.  These are lower-case-t things, but they are not upper-case-T Things.  When I refer to upper-case-T Things I mean actual physical objects made of matter.

One of the distinguishing characteristics of Things is that they exhibit certain regularities in their behavior.  The most important of these is something I call the Law of Location: Things exist in particular places at particular times, and they move between different locations along continuous trajectories.  This is the thing (lower-case t) that allows us to ascribe identity to Things.  We can distinguish (say) this chair over here from that chair over there by virtue of the fact that this chair over here is, well, over here, and that chair over there is over there and not over here.  We can move the chairs so that the chair that used to be over here is now over there, but because the chair had to move in a continuous trajectory we can still meaningfully say that the chair that is now over there (after we moved it) is the same chair as it was before we moved it.

The Law of Location is so deeply ingrained into our psyches that even giving it a name seems like I'm belaboring the obvious, but there is a good reason for it: there are Things — or at least things that appear to be Things — that do not obey the Law of Location.  But again, let's not get ahead of ourselves.

Instead, let's talk more about chairs.  For some reason, chairs are a favorite example among philosophers and religious apologists.  There is a thing in philosophy called the "problem of universals" which asks the question (and I'm just quoting Wikipedia here): "Should the properties an object has in common with other objects, such as color and shape, be considered to exist beyond those objects? And if a property exists separately from objects, what is the nature of that existence?"  In other words, is there such a thing as "chairness", some kind of ineffable chair-like essence which all chairs have in common?  (It sounds a little less silly if you put it in terms of other kinds of properties: is there such a thing as "redness" which all red things have in common?  Is there such a thing as "loudness" which all loud things have in common?)

But this is not about philosophy, this is about science.  Science starts not with abstract philosophical questions but rather with observations, and one of the observations we can make is that chairs are a thing, that is, people talk about chairs and they seem to be able to say coherent things about them.  But what actually is a chair?  When people talk about chairs, what are they actually talking about?

At first glance this seems like a silly question.  Everyone just knows what a chair is.  It's something like this:

But trying to get a handle on exactly what is meant by "something like this" turns out to be not so easy.  What exactly qualifies as "something like this"?  For example, is this a chair?

It is very unlike any of the chairs in the previous picture.  It doesn't have a back.  You can sit on it, but it's a weird kind of sitting where some of your weight is supported by your knees and there is no support for your back.  And what about this?

That is a photograph of a sculpture in Geneva, Switzerland called "Broken Chair".  It looks like a chair.  In fact it looks more like the chairs in the first photo than the one in the second photo does.  It has four legs (notwithstanding that one of them is broken) and a back support.  But you can't really sit on it because it is the size of a multi-story building.  So is it a chair?

And what about this:

This is a (picture of a) Thing that was once a chair, but is it still a chair?  You might actually be able to sit on it, but it only has two legs.  Does a pile of bricks holding up the other side count?  If this is a chair, are the bricks part of the chair?  They are kind of essential to the chair's function, but I think most people would say that they are not part of the chair, that they are merely holding up the chair — if indeed a chair broken to this extent still counts as a chair.

And what about this:

That has four legs and a back and it's the right size, but if you tried to sit on it you would be in for a nasty surprise.

Here is one final example.  This is pretty clearly a chair:

Specifically, it is a folding chair.  It is designed to be folded up so that it occupies less space for storage, like so: 

When a folding chair is in its folded-for-storage configuration, you can't sit on it any more.  So is it still a chair?  Most people would say yes, of course, because all you have to do to be able to sit on it is unfold it.  But the same can be said of broken chairs: all you have to do to a broken chair to be able to sit on it is repair it.  Is there a substantive difference between unfolding a chair and repairing a chair beyond the mere quantity of effort involved?  At what point does the effort required to repair a chair render a chair so broken that it is no longer a chair?

It gets worse.  Suppose we take a broken chair and repair it.  Is it still the same chair as it was before, or is it a different chair?  This question is called the "Ship of Theseus" problem because it was originally posed as a thought experiment about ships rather than chairs, but the puzzle is the same: take any Thing — a ship or a chair or whatever — and start replacing parts of it until at the end there is nothing left of the original.  Is the result the same Thing or a different Thing?

We can make this conundrum even more explicit: Take any Thing that can be disassembled into parts, and a bin of replacement parts.  We can take parts out of the bin and make a new Thing, a copy of the original, but this new Thing is clearly a different Thing because the original still exists.  Now disassemble the new Thing and use the parts to replace parts of the original one by one.  The end of that process is the exact same set of parts that comprised the new Thing that we made before, so this must also be a new Thing.  Indeed, it is the same new Thing as before.  But there is obviously no clear dividing line between when the old Thing became the new Thing.

This lack of sharp dividing lines is fundamental to the nature of Things.  It will become very relevant later when we start talking about the nature of humans and brains and minds and whether or not abortion is murder, but we are getting WAY ahead of ourselves.  For now let's get back to the fundamentals: chairs, and how they relate to the scientific method.  I want to be very explicit about what is going on at this stage in the discussion in those terms.  I am trying to explain some of my subjective experiences.  Specifically, I am trying to explain my gut feeling that the word "chairs" has a meaningful referent in objective reality, i.e. that there really are chairs "out there" in the real world.  The hypothesis under consideration is that chairs are Things, and what distinguishes chairs from non-chairs is some property — chairness — that chairs possess and non-chairs do not.  The hypothesis is that this property is, like the chair itself, part of objective reality, that it's a real thing (though obviously not a real Thing) "out there" in the world.  This position is called essentialism.

Essentialism is problematic for two reasons.  First, it turns out to be really hard to get a handle on exactly what Things are chairs (and thus possess this hypothetical "chairness" property), and second, we can change whether or not a Thing is a chair simply by moving parts of it around.  In fact, we don't even need to move parts of it around.  Imagine carving a chair out of a single (huge) block of wood.  The end result is a chair, and so would have "chairness".  But notice that the only things that moved during the carving process were the parts of the block of wood that were not part of the final chair.  The wood that makes up the chair doesn't move at all.  So where did its final "chairness" come from?  Was it there in the block of wood all along, or was it somehow imbued into the remaining wood during the carving process?

To help answer these questions let us consider a different property: redness, a hypothetical property shared by red things.  We can see that redness is different from chairness merely from the structure of the word.  The word "redness" is built out of an adjective — red — whereas "chairness" is built out of a noun, which is what makes it sound kind of funny.  There is no noun associated with redness, we have to resort to the phrase "red things", which immediately suggests another interesting puzzle: are there any red things that are not red Things?  Does a thing have to be a Thing in order to be red?  Is Santa Claus's coat a Thing?  When a pixel on your computer screen turns red, is it now a red thing?  Is it a red Thing?  The red band in a rainbow pretty clearly has redness, but is it is not a red Thing (because a rainbow is not a Thing).  But is it a red thing?

There is another difference between redness and chairness: chairness (if it actually exists) can be detected using multiple sensory modalities.  Chairs can be seen and touched, so even a blind person can (at least potentially) tell whether something is a chair.  But redness can only be seen -- it cannot be touched or heard or smelled or tasted.  So can a blind person tell if something has redness?  (Yes, they can!  Figuring out how is also left as an exercise, but here is a hint: even normally sighted people cannot see ultraviolet light.  So can normally sighted people tell if something has ultra-violetness?)

But all of this is a distraction.  My subjective perception is that chairs exist and red things exist and other humans exist and (and this is the important part) the vast majority of other humans agree on whether a thing is a chair or whether a thing is red in a huge number of cases.  How do we explain that overwhelming agreement if chairs and red-things — and hence chair-ness and redness — are not real?

Up until about 100 years ago that was still a question open to legitimate philosophical debate, but no more.  The answer is as prosaic (to a modern ear) as it is profound: In the words of Richard Feynman, matter is made of atoms, little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another.  All Things are made of atoms.  But unlike chairs, there are bright lines separating different kinds of atoms.  There are exactly 92 different kinds of atoms that occur in nature, plus a few dozen more than we can produce artificially. Then there are a few variations on those basic types called "isotopes" and "ions", but that's it.  Every Thing that you see is made up of some repertoire of those 92 different kinds of atoms.  What we call "chairs" and "tables" and "red things" are nothing more than different arrangements of these 92 different kinds of atoms.

I don't expect you to take my word for this.  I don't even expect you to take Richard Feynman's word for it.  At this point I am advancing this idea in the same spirit as it was advanced in the 19th century when the idea was still controversial: as a hypothesis.  My burden is to convince you that this hypothesis is better than the essentialist hypothesis, that it is a better explanation for what you observe.  And I have to do this without simply saying, "That's what science says" because that would just be begging the question.

That is what I intend to do in the next installment.  But in the meantime I am going to make a prediction: I don't actually have to convince you that matter is made of atoms.  I'm pretty sure you already believe it.  In fact, I'm pretty sure that your belief is so strong that the mere suggestion that this is a hypothesis that is open to question strikes you as absurd.  Of course matter is made of atoms!  Everyone knows that!

If you don't already believe this, if you are an anti-atomist living in the 21st century, please let me know in the comments.  I would really like to learn how you came to question this.

Field report from Maui

Ulua beach, Wailea-Makena, Maui, before the storm: 

and after:

 

We interrupt this post series to bring you an important weather update

Those of you who watched my debate will know that I was in Hawaii at the time.  Well, I'm still here.  I have no idea if this is making news on the mainland, but Hawaii has just gone through two days of one of the most intense Kona storms in many years.  I have never in my life seen rain this hard go on for so long.  The condo that we are in was not designed for this.  There is a large sliding glass door which is wonderful in sunny weather, but the wind-driven rain was hitting it like a fire hose and driving water underneath the door and into the condo.  And it did this for hours and hours and hours, not continuously, but in wave after wave after wave of pouring rain.  At one point I went outside to try to lay down some towels on the outside of the door to be a barrier against the wind-driven rain and I got completely soaking wet in a matter of seconds.  We did our best to hold back the ride (literally!) with all the towels that we had but it wasn't enough and we ended up with about an inch of water inside.  Fortunately, the cavalry eventually arrived in the form of the condo staff with big plastic bags full of clean towels and they got everything cleaned up.  I eventually figured out how to use one of the plastic floor runners as a makeshift dike outside the sliding door to keep the water from coming in, and since then we haven't had water on the floor, though there is water coming in on some of the walls and making the paint blister.  The main road through the nearby town of Kihei has been washed out, as has much of the nearby beach.  100,000 people are without power across the state (happily our power has stayed on).  It's a horrible mess, though the locals seem to be dealing with it courageously.

If you've been wondering why I haven't been blogging these past few days, that's why.  Trying to stop water from infiltrating your shelter gets a wee bit stressful after doing it more or less non stop for two days.  Things seem to be finally quieting down now, and the forecast is for the storm to finally pass overnight so maybe tomorrow I'll get something done.

Debate Post-Mortem

Last Saturday I did my first on-line debate in four years with a YouTuber who goes by the handle MadeByJimBob (who I will refer to simply as JB since JimBob is not actually his real name and MadeByJimBob is just too long).  The topic was "Is Evolution a Reasonable Position?"  The topic was originally going to be "Evolution on Trial" but I pushed back on that for two reasons.  First, that title had the tacit implication that evolution has been accused of a crime, and second, that the actual substance of the debate would be whether or not evolution is true.  I believe it is true, but I'm not a biologist, so I'm not qualified to defend its truth.  The best I can do is defer to the experts.  What I was willing to do was argue for why I think it is reasonable to defer to the experts in this case.

I can save you the trouble of watching the debate by telling you that JB was constantly interrupting me and, hypocritically, petulantly whining whenever I interrupted him in return.  I didn't want the debate to turn into a shouting match, so I just tried to explain that the questions he was asking could not be answered in a six-word sound bite, and if he actually wanted to hear the answers he would have to stop interrupting me while I was trying to give them to him, but it didn't help much.  So there wasn't much substance.  It was mainly JB asking me questions, interrupting me when I tried to answer, and then shaking his head and condescendingly repeating my name over and over and over.  In his world I guess talking over your opponent counts as a win.

There are two things I could have done better.  One was to put more emphasis on the distinction between defending evolution as a reasonable belief and defending it as the truth.  These are not the same.  There are times when it is reasonable to believe things that aren't true.  The best example of this is the belief that gravity is a force that pulls objects towards the surface of the earth.  That is false, but nonetheless reasonable.

The second thing I should have been better prepared for was to explain why my deference to biologists was not an example of the appeal-to-authority fallacy.  Appeal-to-authority can be fallacious, but it is not necessarily so.  Distinguishing fallacious from non-fallacious appeals to authority is a little tricky, but the best way to do it is to go back to the core tenet of the scientific method: find the best explanation that accounts for all of your observations.  In this case, my observations include the uncontested fact that there are over 100,000 biologists in the U.S. alone, and an overwhelming majority (like 99%) of them agree that evolution is true, which is to say, that all of the diversity of life on earth can be accounted for by naturalistic processes, specifically, random variation and natural selection from a single universal common ancestor.  We can also observe that this community produces a lot of useful products, like antibiotics and vaccines, which is best explained by the hypothesis that they have some contact with reality.

Against this we have a community of creationists who insist that life descended from more than one "kind" but who cannot agree on how many different "kinds" there are.  And it's even worse than that.  It's not that there is an actual dispute over what the number is, it's that none of them will even offer a guess as to what the number is.  [UPDATE: turns out that is not true.]  On top of that, this community has never produced anything of value.  Given all that, it's reasonable for an amateur like me to defer to the judgement of biologists.  They may be wrong, but there is quite a bit of evidence that they are closer to the truth than creationists are.

I was taken aback, however, by a critique from another redditor who goes by DarwinZDF42.  [NOTE: I previously said that this person was Dave Farina a.k.a. Professor Dave.  I got this wrong. DarwinZDF42 is actually someone else.  I apologize to Professor Dave.]

Now, I am about to publicly shame DarwinZDF42.  This is something I hardly ever do.  I don't generally think it's constructive to publicly shame individuals.  And I tried to explain to him in the relative privacy of the creation subreddit why he was wrong, but his response was so dismissive and, frankly, obnoxious that I feel this is warranted.  DarwinZDF42 holds himself out as an expert in public, and so I think it is justified to call out his manifest ignorance in public.

The issue at hand is a question I was asked during the Q&A of the debate: what would falsify evolution?  It's a fair question.  One of the classic criteria for a hypothesis to even be considered as a valid scientific explanation is for it to be falsifiable.  The glib answer of "rabbits in the precambrian" refers to an alleged but unconfirmed quote from legendary biologist J.B.S. Haldane as an answer to that question.  Because there is no original source for the quote, there is no way to put it in context, and so we have to make an educated guess as to what it actually means.  And my educated guess is that it means: if we were to find a rabbit in the precambrian era, that would falsify evolution.

That is wrong.  To see that it is wrong, imagine that I went to DarwinZDF42 and told him that I had found a rabbit in the precambrian era.  What do you think his response would be?  Would he immediately concede that evolution has been falsified, or would he be more likely to tell me that I am full of shit, that there is absolutely no way that there could possibly be rabbits in the precambrian, and so I must be wrong?

Now, on this point I would actually agree with DarwinZDF42.  That would be my reaction to someone making this claim.  It is overwhelmingly likely that the person making the claim is lying or has been deceived, and whatever evidence they think they have that there were rabbits in the precambrian almost certainly has a much more prosaic explanation.  But that is irrelevant to the question of whether this would actually falsify evolution.  To answer that question we have to suspend disbelief and consider a counterfactual world where there is actually persuasive evidence of rabbits in the precambrian.  Would that falsify evolution?

No, it would not (though there is a very small caveat which I will get to in a moment).

To understand why, and to understand the "small caveat", I have to start by pointing out that the word "evolution" actually refers to two different (though related) theories.  The first consists of the following general observations:

1.  There are things in nature that make copies of themselves, i.e. replicators exist.

2.  The copies that replicators make are not always perfect.  There is variation.

3.  Some variants of replicators are better at making copies than others.

4.  Which variants are better at making copies depends to some extent on the environment the replicator finds itself in and the variants it has to compete with.

5.  There is a large variety of different environments on earth, and so you naturally get a large variety of replicators.

Those observations lead to a conjecture: that 1-5 are a sufficient explanation to account for all of the variety of life on earth, and that it all descended from a single common ancestor.  No designer is necessary.

Notice that all of this seems plausible even before we look at any actual data.  As framed above, it is a theory that does not require any fossils or trips to the Galapagos.  Democritus could have come up with it.  (In fact, had Democritus actually considered this problem, he may well have even predicted the existence of cells the same way that he predicted the existence of atoms!)

The second thing referred to by "evolution" is a very detailed historical reconstruction of how the current repertoire of life on earth actually arose.  That, of course, is impossible without actual data, and it is bound to be complex, messy, and incomplete, constantly being refined and revised as new data comes in.  Until we have unearthed the last fossil on the planet, this will be a work in progress.

A cornerstone of this historical reconstruction is the so-called Cambrian explosion, a period of very rapid creation of new species.  The Cambrian explosion began about 540 million years ago (MYA) and was followed by the Devonian period (420 MYA) when the first land animals appeared, the Mesozoic (256 MYA) a.k.a. the dinosaur era, and the Paleogene (66 MYA) when the dinosaurs got wiped out and opened the door for mammals to become the dominant land animals.  The earliest known rabbits appeared about 55 MYA.  (And of course all of this is an extreme oversimplification.  There is a reason people make their living studying this stuff.)

So finding a rabbit in the precambrian would certainly be remarkable.  It would be out of place by a few hundred million years, which would surely cause a major upheaval and revision of the currently accepted timeline.  It would probably be the biggest such revision ever.  But would it falsify evolution?  Would it cause the scientific consensus to suddenly accept young-earth creationism?

Almost certainly not.  I can think of many more plausible explanations.  A hoax.  A local event that somehow transported a rabbit fossil into a precambrian geological layer.  A previously unknown geological phenomenon that somehow produced something that looks like a rabbit fossil but actually isn't.  Or even an entirely new and previously unknown period in earth's evolutionary history, the evidence of which is mostly lost to subduction.

Note that that last possibility could plausibly be considered "falsifying evolution" but only in a very narrow sense.  It would falsify part of the current reconstruction of earth's past.  A big part to be sure, but still, only part.  But it would not falsify the central tenet of evolution, that all of life can be accounted for by naturalistic processes proceeding from a single universal common ancestor.  Which is to say, it would (almost certainly) not falsify evolution in the sense intended by the person who asked the question.

So to the question of what would falsify evolution, the glib response "rabbits in the precambrian" is at best just barely defensible, and at worst flat-out wrong (which is one reason to doubt that Haldane ever actually said it, or if he did say it, that he actually meant it, because he was probably smarter than that).  Under no circumstances is it justifiable to berate someone for failing to offer it in response.  That is wrong on so many levels.  Even if rabbits-in-the-precambrian were defensible, there is no excuse for someone who holds themselves out as a science educator to use the condescending and dismissive tone that DarwinZDF42 used with me.  That is never the way to win hearts and minds.  With people like DarwinZDF42 on our side, it's little wonder that the war on misinformation is being lost.