Again on ageing as a disease: A rectification

My previous post was somewhat confusing even to myself. To be completely frank, I think it was a little bit of a fuck-up. Several people have commented about it, for example on Reddit or Facebook, pointing out among the rest that whether or not ageing is a disease isn’t just semantics and it isn’t pointless. (To the people commenting on Facebook, I’d like to say that I’m sorry I didn’t reply to your comments, but for some reason I was stuck as ‘Rejuvenaction’ on those posts, and Pages don’t seem to be allowed to comment on group posts. I tried to switch to my personal account to no avail. I figured out a workaround, but at this point it’s a bit too late.)

What I meant to say is that arguing whether or not ageing is a medical condition is far less important than treating its root causes, and as long as we focused on this task, we could postpone the debate to a later time. The finer points of establishing if ageing fits the definition of ‘disease’ to the letter would waste precious time we could spend saving lives instead; we should definitely not wait until the issue has been settled before we start developing rejuvenation biotechnologies. (And we are not waiting at all, luckily.) However, classifying ageing as a disease is very important and not at all pointless, as Reason of FA! explained in this post. In a nutshell, if the ageing processes that lead to age-related diseases were considered pathological, research on how to interfere with them would likely receive more funding, and drugs that target ageing itself could be approved by the FDA. (The FDA only approves drugs that target recognised diseases; if ageing isn’t recognised as one, no drugs targeting it would be approved.) I think there might be a chance that some bona-fide anti-ageing drugs would be approved even if ageing wasn’t recognised as a disease—for example, drugs that clear the amyloid plaques that build up in the brain would essentially be rejuvenation therapies preventing Alzheimer’s disease, and as such I suppose they would be approval material for the FDA, even if they did’t recognise ageing itself as a disease; nevertheless, it’s clear that things would be easier in terms of getting funding and approving drugs if the whole ageing process was classified as a disease.

That being said, if we want to decide if ageing is a disease, we really do need to have good definitions of both terms. It turns out that defining ‘disease’ is not a simple problem, and apparently WHO themselves don’t have an official definition. They do have a definition of health, though, which says among the rest that ‘ Health is […] not merely the absence of disease or infirmity’; the lack of an official WHO definition of disease makes their definition of health a bit problematic, in my opinion. I suppose they rely on the intuitive idea of ‘disease’ we all have, but as a mathematician, I find this decidedly insufficient. If you look up ‘disease’ on Wikipedia, you’ll find this:

A disease is a particular abnormal condition, a disorder of a structure or function, that affects part or all of an organism.

I don’t like this definition very much, because it might imply that a ‘normal’ condition isn’t a disease; however, the incidence of age-related disease grows higher and higher with age, to the point that I don’t see how they couldn’t be considered ‘normal’ past a certain age; that’s why I prefer a definition along the lines of ‘a definite pathological process having a characteristic set of signs and symptoms’.

As for the definition of ‘ageing’, I stick to Aubrey de Grey‘s definition, i.e. that ageing is the process of accumulation of damage the body inflicts itself as a side-effect of its normal operations. In the post we’re discussing, I said that even according to this definition, ageing wasn’t a disease, but only a cause of disease; I used a comparison I found very fit, i.e. that ageing is to age-related diseases what viruses are to infections. However, upon more careful reflection, this comparison is a bit misleading. It’s true that a virus is not a disease; however, a virus isn’t a process either, unlike ageing. A better comparison would be between age-related damage and viruses. The accumulation of damage could then be (rather loosely) compared to an infection, in the sense that both are processes that happen over time: They begin, they progress, and eventually give rise to symptoms and full-blown diseases.

Now, at least according to the second definition of ‘disease’ I provided, ageing seems to be one, because it is a pathological process (although an extraordinarily long one) that has a characteristic set of signs and symptoms. While symptoms and visible signs of ageing don’t show up until late in life, more subtle signs (accumulation of senescent cells, or cross-links, for example) are present inside your body basically at all times. The reason I call it a ‘pathological’ process is that the damage caused by ageing is, as said, a side-effect of your metabolism; it’s a bug, not a feature, left around by evolution because it was generally not serious enough to prevent you from reaching reproductive age. It’s a disease that stays silent until a certain threshold is reached—again, pretty much like an infection until there are enough viruses around to wreak havok.

Ultimately, ageing may or may not be a disease depending on the definition of ‘disease’ we want to adopt. With enough nitpicking, ageing may well not be a disease according to some definitions, but in principle we could change definitions around so much that Alzheimer’s disease stops being a disease and mountain climbing suddenly becomes one. (This is an intentionally ridiculous example.) I have no problem admitting that this is not what my previous post seemed to say, and I honestly have no idea how I managed to twist my own thoughts around so much that they ended up contradicting things I wrote before. I have a hunch I had grown a bit too fond of the metaphors I used in that post, which again seemed fitting but were confusing. I’m not a fan of revisionism, so my previous post is going to stay up right the way it is, just with a link to this one.

As a side note, some now-recognised age-related diseases were considered to be part of ‘normal’ ageing in the relatively recent past. Seems to me ‘normal’ is a safety-blanket word that we use to feel okay about not doing anything to change something that is not good and difficult to change. Or maybe, it’s just that we like feeling ‘normal’. If you’re 78 and your doctor says you’ve got high blood pressure, he’ll also probably reassure you and say that ‘at your age, it is normal’. So what? That only means that it’s common for a person of your age to have unhealthy blood pressure, and it’s in no way different from saying that it is normal for a smoker to have their lungs full of crap. It’s normal alright, but it is very bad nonetheless.

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Reductio ad absurdum

If you’ve ever tried to advocate for rejuvenation, you know it is hard. Usually, people deem the idea as crazy/impossible/dangerous well before you get to finish your first sentence. Living too long would be boring, it would cause overpopulation, ‘immortal’ dictators, and what you have. However, you’ve probably never heard anyone use the same arguments to say that we should not cure individual age-related diseases. This is largely because people have little to no idea about what ageing really is, and how it cannot be untangled from the so-called age-related pathologies. These are nothing more, nothing less, than the result of the life-long accumulation of several types of damage caused by the body’s normal operations. Unlike infectious diseases, the diseases of old age are not the result of a pathogen attack, but essentially of your own body falling apart. As I was saying, people are largely unaware of this fact, and therefore expect that the diseases of ageing could be cured one by one without having to interfere with the ageing process itself, as if the two weren’t related at all. The result of this false expectation would be that you could cure Alzheimer’s, Parkinson’s, etc., but somehow old people would still drop dead around the age of 80 just because they’re old. That’s like saying they died of being healthy.

Back to reality, this can’t be done. To cure the diseases of old age, you need to cure ageing itself. If, for whatever reason, you think that curing ageing as a whole would be a bad idea and it should not be done, the only option is to not cure at least some of the root causes of ageing. Consequently, some age-related pathologies would remain as untreatable as they are today.

Now, the typical objections raised against rejuvenation tend to sound reasonable at first. To some, the statement ‘We should not cure ageing because it would lead to overpopulation’ sounds self-evident. However, if we consider the implications of this statement, things start getting crazy. As said, not curing ageing implies not curing some of its root causes, which in turn implies not curing some age-related diseases. Therefore, the sentence ‘We should not cure ageing’ implies ‘We should not cure [insert age-related disease here]. What happens when we reformulate typical objections to rejuvenation in this fashion?

  • Generic:
    We should not cure ageing, because otherwise fewer people would die and this might lead to overpopulation.
  • Specific:
    We should not cure Alzheimer’s disease, because otherwise fewer people would die and this might lead to overpopulation.

  • Generic:
    We should not cure ageing, because it would be unnatural.
  • Specific:
    We should not cure atherosclerosis, because it would be unnatural. (The f*ck did I just read?!)

  • Generic:
    We should not cure ageing, because it would be only for the rich and cause inequality.
  • Specific:
    We should not cure cancer, because it would be only for the rich and cause inequality. (THE F#CK DID I JUST READ?!?!)

  • Generic:
    We should not cure ageing, because there are more urgent issues.
  • Specific:
    We should not cure type 2 diabetes, because there are more urgent issues. (Right. Now let me watch this new Hollywood mediocre blockbuster whose making was an absolute priority.)

  • Generic:
    We should not cure ageing, because longer lifespans would be boring.
  • Specific:
    We should not cure cerebrovascular diseases, because longer lifespans would be boring. (Well, I can see how an ischemic attack would spice your life up.)

  • Generic:
    We should not cure ageing, because the future looks too grim to live.
  • Specific:
    We should not cure arteriosclerosis, because the future looks too grim to live. (We should not cure all age-related diseases—effectively making the future worse than whatever it looks like right now—because some people think the future will be so horrible that THEY won’t want to live any more and for some weird reason specifically prefer to be killed by an age-related disease, even though all of this incidentally implies that most of the rest of the world too will die of age-related diseases, including those who disagree with this crazy argument. Sounds reasonable.)

I don’t think I need to point out why the statements listed under ‘specific’ are utterly ridiculous. (Which, in case you were wondering, is the reason for the title of this post. It’s latin for ‘reduction to absurdity’ and it is a type of mathematical proof, also known as proof by contradiction. What I did here is not a proof by contradiction, but the ‘reduction to absurdity’ bit is definitely there.) I’m all for discussing potential problems brought about by the defeat of ageing, so that we can prevent them from ever happening; however, I’m not going to buy a pig in a poke and accept blatant nonsense as valid objections to rejuvenation. Also, choosing which age-related diseases should be left untreated for the sake of not curing ageing as a whole is not an interest I’m planning to pick up any time soon.