Friday, December 19, 2014

On the nature of evidence: the requisition of science

Evidence is a wonderful thing.  It shows us what is real and what sorts of things to be true in our universe.  This is why it is important to understand the role it plays in our lives, as well as the sort of rigors that are required to ensure science remains as objective as possible.

Note: this article isn't discussing the difference between evidence and proof. I am going to treat the terms as completely commensurate for this post to avoid semantic posturing and pedantry.

Some people have a hard time understanding what evidence is.  Evidence comes in two forms, and both are based on observation. 

The first type is direct evidence.

Some evidence we can view, touch, taste, feel.  Direct evidence for a fire is watching it burn.  Direct evidence for waves and tides is watching them on the coast at the ocean, for example. 

The second type is indirect evidence.

Some evidence is observable after the fact, or in the absence of things we can do right now.  Ashes are a good indicator that something was, at one time, on fire.  The sides of cliffs eroding in particular ways, or accumulating things to only a certain level, are good evidence of waves and tides, respectively.
Understanding this is key to understanding science, and to scientific understanding of nature.

This is where it is important to understand things that are not evidence.  A science textbook is not itself evidence for science.  It is a textbook that explains testable things that have happened in the past ( note: in a meta sense, any book is evidence for science because you can do things to the books, like set them on fire or weigh them to measure gravity or test their ability to withstand ionizing radiation...).  The fact that a science text exists (and there are write a number if science and math texts in the world) doesn't make it evidence for the things contained within.  The fact that we can test the ideas contained within, however, does.

This same rule applies to any text. The bible is not, as Ken Ham implies (for example), evidence for the Genesis creation story.  (Again, in a meta sense, we can and are testing the ideas there too - Sodom was probably pretty tame compared to Las Vegas, but it still thrives.  China is considerably less Christian than the ancient Midianites, but still it stands).

This tends to trip up people a bit, who think that creation and evolution have the same credibility.   Lots of religious people want to say, for example, that the fossil record is faulty or too incomplete to make an informed decision.  Let's take a look at this stance from the evidence.

To save time, we are going to break this argument down to a couple simple concepts in the greater thing.  First, it is important to note that fossils are all intermediaries. Every species is intermediary.  DNA supports this also (evidence isn't evidence without other evidence to verify, mind).  If we only had fossil evidence, then the idea that every species is unique would also hold water.  We have not only fossil evidence, but also DNA evidence, and similarly we only find given species within various strata of rock that have consistent radioactive timers encasing similar creatures.  One single fossil too far back would be enough to make us see that the other view could require more evaluation.  As yet, it hasn't been found.

So, you ask, where is the testable part of this?  Well, that is the important thing, and the burden of proof is mine. Here we go.

You, me, or anyone can go and start digging up (within reason: please don't go breaking laws, and be safe) the ground and see what fossils we can find.  We can get a Geiger counter any test the radioactive content of the rocks.  We can borrow a mass spectrometer and determine what elements are in it for the decay and it's half life.  We can do the maths on our own to determine our method are good.  We can view other, carefully recorded things, which are verified by more than one observer. 

I think we can see why religious books don't meet this criteria, but in the interest of being thorough, let's analyse the antecedent.  Let's say god really did create each kind of 'animal and plant' in existence.  Let's even skip some of the simpler aspects and jump to Noah.  Noah supposedly saved one of each gender of each type of thing.  Let's even forget about the species of bacteria and flies we can make in labs in a matter of a lifetime, or the different breeds of dog that didn't exist 200 years ago and will likely be species in another 200 or so.  Now let's analyze this through the bible.

One of each kind of animal is A LOT of animals.  It is considerably fewer if we only count the animals Noah would have known about, living essentially in a desert.  But alas, we have indirect evidence that Noah has literally a viable copy of at least every single animal that exist today, plus the ones we know have gone extinct even in our lifetime.  It is important to note that Noah only saved land animals, and that a dove basically found a tree god popped into existence on a fertile plot of land good popped into existence at the 'end' of the worldwide flood. 

Anyway.  My name isn't Randall Munroe, but I am gonna take a shot at a what-if.
What if Noah really did take one of each animalHow big would the ark have to be?  What other interesting things does this tell us?

The first thing is calculating how many animals exist today.  Since I am writing this from my phone, I'm going to use Munroe's style of estimation and leave the math as an exercise to the reader (see if my evidence adds up with your evidence!  Hahaha!  Math jokes!) or the professionals.

Let's look first at the zoos of the world.  Most zoos don't even have 1% of all species (kinds?) in the world, let alone even a representative for each kind of animal (species, genus, family, phylum, who knows.  Kinds are a nice device, eh?).  So we need a boat that can handle, let's say, every current species bigger than a gnat.  And it had to fit all in a boat 500 cubits or so long, among other dimensions.

There are at least two species of elephant.  There are at least ten species of big cat.  There are thousands of marsupials (kangaroos to kookaburra and things in between).  There are likely at least as many species of lizard and mammal and insect and arachnid and crustacean ( not all crustaceans live in the water, and many would die if the world were inundated for over a month.). So let's pretend there's only ten major families of animal.  Let's define them too, since this is science and all.

Mammals, arachnids, crustaceans, marsupials, avians (which, admittedly, fall into most of the others), lizards, reptiles, insects, and some others that are primarily not land dwellers.  Let's say, just to simplify, there's at least a thousand things in each.  So we need room for at least five thousand unique pairs of animals, plus a family of humans, enough rations for a family of at least 20 people (remember, the bible probably omitted lots of women that Noah and his brood would have had) to live for an indefinite period in a time before preserving food was really a thing at all, let alone other various things we take for granted.  It isn't clear if God simply made every animal immune to hunger, thirst, and lots of other things, or if Noah had to prepare food and stuff for them (he did prepare and plan for months of animal bedding, at the very least), or if the number of species simply dwindled as the carnivores are the herbivores. Let's pretend god magically made every animal on earth tame for very brief period of time, and that every species survived because of that magic manna god used later in some desert.

So we have, let's say, ten thousand pairs of animals on a boat.  500 cubits is definitely not more than about 700 feet.  Let's assume this is a square boat, and let's be generous in Noah's arm length.  Let's say this thing is a cube, rather, three football fields long and the football fields wide.  Let's say it is, quite unrealistically, ten floors.  Noah probably didn't think to make the floors varying height to most efficiently accommodate carrying heights per floor (I don't recall and my phone isn't getting internet here, but I think for some reason it was only three floors or so, and Noah had access to all of them). 

So how many animals can we fit on 90 football fields?  226 per field is approximately what we need, that's 112 of each gender, for just 10,000 animals total.  I think it would be hard to fit the thousand representative mammal species in that area, let alone a pair of every species of mammal.  People don't realize, there are lots of animals in the world.  Primates alone would not fit one of each on a single field.  That's us, chimps, bonobos, baboons, gorillas, true monkeys, orangutans, lemurs, et cetera.  Not let's include dogs, wolves, cats, lions, cheetas, hyenas, gazelle, water buffalo, caribou, elk, gnu...

So, it seems the direct evidence of a very large number of species is indirect evidence against the Noah's Ark hypothesis.
And that, my friends, is why evidence is important.

Part two to follow, perhaps?  INDUBITABLY!