Saturday, February 5, 2011

Biological Immortality

In the February 2nd, 2010 Deakin Philosophical Society meeting, we discussed the idea that humans may one day no longer age (after watching a TED lecture on the subject by Aubrey de Grey, which can be found here). In the discussion the followed, there seemed to be a disagreement which, in my opinion, hinged on a fundamental misunderstanding on how each party in the discussion was defining the term ‘immortal’; one side (my side, for those of you playing at home) was using a more biological definition of immortality, the other was using what might be the more colloquial sense of the word (namely, never having to die).

My take on the word immortal (at least, my usage of in during this debate) was more in line with biological immortality. The basic, one sentence summary of this concept would be where the death rate of an organism is not affected by the age of the organism. With humans (and animals in general), once adulthood is reached, the probability of an individual dying in the following year increases (that is, the older you are, the more likely you are to die). This graph from the Australian Bureau of Statistics illustrates the idea nicely:

Biological immortality would be represented in a graph like this:

That is, once adulthood was reached, the death rate would remain static (more or less). This is not to say people would not die, just that there would be no correlation between age and death rate. There would still be a correlation between life style choices and death rate (i.e. if you drink and drive, you’d have a higher probability of dying than someone who didn’t drink drive).

In using ‘immortal’ in this sense, I believe it is perfectly acceptable to say that humans will one day become immortal.

It should be noted that there may still be an indirect correlation between age and death rate in a biologically immortal race; it is possible that life would become mind-numbingly boring after many hundreds or thousands of years. Thus, the older people get in a biologically immortal society, the more likely they are to choose death.


  1. Re: your last paragraph. Zardoz anyone. :-) I quite agree bio immortality (non-senescence of the organism) will be a reality within fifty years, but one of the primary challenges with it will be the brain: unless we genetically engineer it to behave differently, it will run out of space relatively quickly, which will create a permanent inability to learn/remember anything new.

    We will either have to reprogram brains in some brilliant way to destroy and overwrite old memories in order to make room for new ones (and that's the least desirable option, especially given its potential to go wrong), or we will have to cybernetize our brains (have some sort of integration between the biological brain and electronic memory storage, which will likely also require genetic reengineering of the brain), or replace them entirely (with infinitely upgradable electronic brains).

    BTW, thank you for the book gift! And for any more to come in future (though I certainly don't expect any more!).

    P.S. My wife just amusingly remarked that Lord Bishington sounds like a character in a Jeeves & Wooster story. "Except they'd call him Bishy," she says. But maybe you'd have to be familiar with the franchise. :-)

  2. *Nods* I've always found the discussion of cybernetic enhancement/replacement of the human brain facinating. As a thought experiment, it is a nice demonstration of that the mind and brain are the same thing. In that, I've often presented the idea to dualists as follow;

    If you started replacing neurons with synthetic analogues that behaved exactly the same as their biological counterparts, at what point would the mind cease to exist? Or would the 'immaterial mind' find a way to interact with the new, synthetic neurons?

    But yes, I rarely buy books off Amazon (I store them up in my cart and buy them in bulk), so while it may not be frequent, you can expect more books. My reasoning is that if it helps you continue doing what you do, even in some small way, I feel it is worth it.

    By the way, I have already added you on Facebook, but, in case you want to put a few more details to my face/internet persona, here is my profile:!/lordbishington