What are the chances of YOU being born? This is not just a speculative question, but an empirical question which can be answered, albeit roughly, with simple analytical mathematics. Before I start I need to make an important assumption: everyone born, past and present, have a unique consciousness based on their genetic makeup. I don’t want to get sidetracked by a discussion of what is, or how we define human consciousness, fascinating as the topic may be.

It is not unreasonable to consider each human to have a particular unique
consciousness. We know that identical twins are ‘genetically identical’ and yet
each twin has its own conscious identity and reality. This is not strictly true
as identical twins will differ in the realm of gene expression due to the
mechanism of epigenetics. Again, I don’t have the space to consider the
fascinating world of epigenetics- perhaps in a future post?

Firstly,
let us consider the probability of say, your mother and father actually
meeting. I’m going to have to fudge this a little as every case will differ
with regards to probability. I’ll, for the sake of gross simplicity, assume
that the odds of your father and mother actually meeting are 1 in 20,000 and
say the chances of them liking each other and producing issue (ie you) is 1 in
2,000. You can argue that this is pure guesswork and you would be right. This
part of the equation is the most inaccurate, but as you will see, it will have
only a small bearing on the rest of the calculation.

Thus far
we have a probability of

**20,000 x 2,000 = 40,000,000 (forty million)**. But this is only the beginning.
For you
to be you, a specific egg melding with a specific sperm is required. Each sperm
and egg is genetically unique due to a biological process called meiosis. A
normal man will produce about 12 trillion sperm in his reproductive lifetime
and a fertile woman harbours 100,000 eggs or ova. We need to take into account
that men are fertile throughout post-pubertal life while a woman stops
ovulating when she hits the menopause. For the sake of this calculation, I'm
going to say that a third of the sperm will be available during his partner's
fertile period. Thus we can calculate the odds of you coming into existence due
to one unique sperm meeting one unique egg as:

**4 trillion x 100,000 = 400 quadrillion.**But we have to take into account the rare union of two people coming together in sexual congress, as previously calculated as 40,000,000 (forty million). Therefore, the odds of you coming into existence are:**40 million multiplied by 400 quadrillion, which equals 16 septillions.**Before continuing a slight digression is required (no shit, Flaxen). When dealing with large numbers it is convenient to apply the concept and notation of ‘the power of 10'. If you are unfamiliar with this mathematical notation, a quick gogle search will help you understand this convenient and practical mathematical shorthand. In fact, it is impossible to formulate the mathematics of 'big' numbers without the power of 10 notations. Therefore, our previous calculation can be rendered thusly:**40**

^{6}x 400^{15 }= 16^{24}.**Hold onto your hat, this is where it starts to get a bit weird**

Tis not
all about YOU. Next, you have to consider the preceding generations. The fact
that you have been born at all means that all your ancestors made it to
reproduce. Any break in the chain results in your non-existence
(?!). And at each generational stage the same probability
previously and lovingly worked out will apply. So how far shall we go
back? Perhaps to the first human? However, this is not a discrete event in
time. To gain a realistic figure we should continue back in time to your very
first ancestor hanging around in the primordial soup/slime- a single-celled
organism 4 billion years ago, called Ralph. To stop the numbers from getting
REALLY BIG I’m going to consider just our humanoid lineage. I’m making the
assumption that human/humanoid like organisms (I’m not including ‘Tipton Man’)
have been around for 3 million years (3

^{6}years). This would represent about 150,000 generations (150^{3}). After applying the mathematics previously given we have a probability of**1 in 10**). I’m not going to put forth my mathematical reasoning here, otherwise, this post will be way too long…….. Of course, you could have a go yourself in the comfort of your own home.^{2,640,000 }(10 followed by 2,640,000 zeros
Tis time
to gain perspective and provide comparisons.

The
number of stars in the observable universe: 7 x 10

^{22}
The total
number of fundamental particles in the observable universe (diameter 93 billion
light years): 3 × 10

^{80}
The
smallest possible length is called a Planck length which equals 1.6 x10

^{-35}m and the number of Planck lengths present in the volume of the observable universe: volume in “Planck cubes” ≈ 2.2×10^{183}.
The point
I'm trying to make is that the odds of you existing are so infinitesimally low
that your existence is impossible- but there you are, glancing at this page
(hopefully in wonder) whilst drinking beer and scratching your gonads. And this
analysis only takes us back to the first humanoid, before that there are
another 4 billion years to take into account. This probability, if I could be
arsed to work out, would take us into the world of hyper-maths.

There are
other probabilities we could layer on, such as, the probability that the Earth
is able to sustain life and the probability that life actually got started and
evolved. And of course, we could delve back further............

Brilliant! This post made for fantastic reading. Your others have been excellent, but for me this eclipsed them all. Thank you.

ReplyDeleteErr, 100,000 eggs but usually only one is prepared for fertilisation every lunar month. With approx 40 years of fertility, a woman has a maximum of 520 "windows of opportunity", not 100,000.

ReplyDeleteHi Ed, tis true that only 500 or so see the 'light of day', but the available pool of eggs sitting in situ within the gonads is 100,000.How the eggs are chosen to ovulate from this store is another mystery.

DeleteAlice Robert's book: The Incredible Unlikeliness of Being: Evolution and the Making of Us is a brilliant read on this very subject.

ReplyDeleteThanks TonyF, I wasn't aware of the book- I'll look it up.

DeleteMr P, how's the weather in Ireland, these days?

ReplyDelete