Tag Archives: Science

How to prove that space is curved…

Cosmology, Mathematics, Physics, Relativity, Science, The scientific method, Time, , , , , , , , , , , ,

Question: if you lived in flatland (a 2-d world), how could you tell if the land was curved in the third dimension?

Answer: geometry!

It turns out many of the mathematical rules we learned at school ‘fall apart’ if the working surface is curved. For example, can you draw a square on the surface of a sphere? No!

So can we use this insight to tell if our 3-d world is curved in a mysterious fourth dimension? Yes!

If we set off from earth, went in straight line for, say 1 light-year, then turned 90º, went 1 light-year, turned 90º again, and then did this yet again, you should have traced a perfect square, and be back exactly where you started. If you aren’t, something is amiss!

 

Now it turns out that it we do this, we will indeed discover an error; but why? And how do we know this?

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Newton told us that a massive object in motion will continue to travel in a straight line, unless acted upon by external forces. Some people think that Einstein overturned this insight, but he didn’t; indeed he extended it: he said that the force of gravity is not actually a force, and thus objects falling under gravity are actually going in straight lines! Indeed this makes sense, as anyone ‘falling’ does indeed not sense any acceleration, but rather feels ‘weightless’. Thus they are not actually accelerating, they are going straight – in curved space.

Now anyone who has thrown a ball can see this is absurd on the face of it, but Einstein was serious, and he is right, from a certain perspective. The ball is not going in a straight line through ‘regular’ space, but is going on a straight path in a 4-d construct called ‘space-time’. Likewise, he would argue that the planets are tracing straight lines around the sun; and indeed the ‘parabola’ of a baseball is actually not a parabola, but a very small part of the enormous ellipse that would be traced in the baseball could fall though the earth and go into ‘orbit’ §.

Anyway, Einstein’s model says that light travels in straight lines, but we have seen that light bends when it passes near to the sun (this can most easily be tested during an eclipse) – so… if one of the sides of your ‘perfect square’ were to pass near the sun, it would also be bent and if you followed the above rule to draw the square, you would not end up where you started.

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Physicists have grown used to Einstein’s model, and better tests for the flatness of space have been developed. For example, if you drew a circle on the surface of a sphere, the area would not equal Πr2, but would be less. Likewise, in 3-D space, we could plot a sphere and then measure the volume and if it did not equal 4/3Πr3, we would know something was amiss.

So physicists have looked at how light bends, and how the planets move, and found out, amazingly (but predicted by Einstein) that the error in this spherical volume calculation is directly proportional to the mass of matter within the sphere – proving that the warpage in space is proportional to (and thus caused by) ‘mass’.  Thus mass warps space.

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MC Escher: 'Grid'

But is space really warped in some ‘extra’ dimension?

Well, this is a good question. Maybe it is some extra ‘spacial type’ dimension, but you could also look at time as a fourth dimension, and argue that this space is not ‘curved’ at all, but rather that space and time simply vary in density in different locations. I personally like this way of looking at it, it eliminates the need for some vague ‘extra dimension’, and therefore swiftly removes the possibility that space could be ‘closed’ or fold back on itself in this extra spacial dimension. Occam’s razor thus prefers the ‘density’ model!

Footnotes:

§. In Wikipedia, they state that balls bounce in perfect parabolas, but note they also mention a ‘uniform’ gravitation field, and it is well to remember that the earth gravitational field is not uniform, but radial. Thus I stand by my assertion that missiles follow elliptical paths just like planets and comets. Of course, an ellipse is a close relative of both the parabola and the hyperbola, so this is not really that dramatic.

Good reading for anyone wanting to be more energy efficient…

Economics, Education, Environment, In the media, Science, Science communication, , , , , , , , ,

I am busily researching a series of articles on energy, and thought htis article deserved an immediate link…
http://www.environmentmagazine.org/Archives/Back%20Issues/September-October%202008/gardner-stern-full.html

Did you know…

Physics, Science, Science communication,

…that… Magenta Ain’t A Colour?

A nice bit of odd science from Liz Elliot.

It turns out that the block below is not a regular colour (wavelength of light), but a clever thing your brain has done, especially for you. Nice.

Magenta!

Of course, that is true for all colours, they are projections from our brains onto the world. The world itself has no colour, only common EM signatures we recognise and label with what we call ‘colour’. Gotta admire the brain, really.

Skeptics vs Deniers

Environment, In the media, Philosophy, Science, Science communication, Skepticism, The scientific method, , , , , , , , , , , , , ,

There is a growing movement, grassroots in nature, but starting to connect, called the skeptics community.

Who exactly are they? Are they people who are starting to uncover the truth – that most world governments are a sham and that secret societies control our every move? Do they deny the holocaust and suspect 9/11 was a complex plot?

No.

A skeptic is merely someone who needs to be convinced of things through reason, rather than one who accepts things on some-one’s say-so.

Simple!

So what is a global warming ‘skeptic’?

Climate science is complex, and consensus opinion is that man’s activity has led to increased greenhouse gas emissions which are likely to reduce outgoing radiation and thus lead to a net shift upward in the temperature of the Earth’s delicate surface. Yes, there are other possible causes, yes, the models contain assumptions, and yes, some fools have fabricated data to look cool. It is also true that many respected scientists will not say it is a cast iron ‘fact’.

So that is the scene – and there seem to be a few types of stakeholders:

  • the ‘global warming denier’
  • the  ‘global warming skeptic’
  • the regular ‘skeptic’
  • and lastly, the gullible!

A ‘global warming denier’ has come to mean someone who does not think the evidence stacks up enough to warrant concern, or worse, thinks it is all a giant conspiracy.

A ‘global warming skeptic’ has come to be somewhat synonymous with a denier, but perhaps without the conspiracy angle. However, many are just people who are on the fence – they are often very smart, and don’t just believe what they are told, but on the other hand, they are easily misled, as there is just so much misinformation out there. They may be the ones who say “I heard the jury is out…” rather than actually looking at evidence.

Some legitimate scientists have foolishly allowed themselves to be given this label, just because they debate some small details (like the rate of heating, or the likely nature of socio-political impacts). These scientists are then lumped with deniers. Tough luck to them.

I found this is some random folder on the 'net. If it's yours, please let me know, I love it! Update: it looks like it may well be from thisisindexed.com - click it to link - nice one Jessica Hagy!

Now a true skeptic will weigh all evidence according to the following principles:

  • is it logical?
  • does it conflict with other strong theories? If so, is it strong enough warrant a change to your previous understanding?
  • is there independent corroboration?
  • do the proponents have a  proven track record (credibility)?
  • is there any incentive by stakeholders to twist the facts?

This describes most good scientists, so its not a bad thing.

In the case of global warming, most true skeptics who have looked closely at the evidence and weighed it appropriately, agree that there is real cause for concern.

But yes, we skeptics will always retain just a little doubt, because you just never know…

Energy Explained in One Page

Economics, Education, Environment, Philosophy, Physics, Science, Science communication, The scientific method, Things Explained, , , , , , , , , , , , , ,

Ok, so we all want to be good to the environment. The first step to doing this, as is often the case – is to understand the main characters in the story – and possibly the biggest character in the story in Energy.

However, energy is such a very vague concept, so where do you go to learn more? Do you have to do a physics course?

I don’t think so, and to test my theory, I have tried to explain energy as briefly as I can in this post.

Energy 101

Energy is what makes the world go round. Literally. Every neuron that sparks in your brain, every electron that fires down a wire, every molecule burning in a fire, carries with it a sort of momentum that it passes on like a baton in a complex relay race. The batons are flooding in all directions all around us and across the universe – they are energy and we have learned how to harness them.

The actual word “Energy” is a much abused term nowadays – because energy is used to represent such a disparate range of phenomena from heat to light to speed to weight, and because it seems to be able to change forms so readily, it is cannon fodder for pseudo-scientific and spiritual interpretation. However, you will be pleased to hear that it actually has a very clear (and consistent) nature.

I like to think of energy being a bit like money – it is a sort of currency that can be traded. It takes on various forms (dollars/pounds/swiss francs) and can be eventually cashed in to achieve something. However, just like money, once spent, it does not vanish. It simply moves on a new chapter in its life and may be reused indefinitely.

§Energy currencies:{1}Matter is energy(see footnotes) {2} Radiation {3} Chemical energy {4} Thermal (heat) energy {5} Compression energy {6} Kinetic (movement) energy {7} Electrical energy

To illustrate the point, let’s follow a ‘unit of energy’ through a visit to planet Earth to see what I mean. The [number] shows every time it changes currency (see the key on the right).

The energy starts off tied up in hydrogen atoms in the sun [1]. Suddenly, due to the immense pressure and heat, the nuclei of several atoms react to form a brand new helium atom, and a burst of radiation[2] is released. The radiation smashes into other nearby atoms heating them up so hot [4] that they glow, sending light [2] off into space. Several minutes pass in silence before the light bursts through the atmosphere and plunges down to the rainforest hitting a leaf. In the leaf the burst of power smashes a molecule of carbon dioxide and helps free the carbon to make food for the plant [3]. The plant may be eaten (giving food ‘Calories’), or may fall to the ground and settle and age for millions of years turning perhaps to coal. That coal may be dug up and burned to give heat [4] in a power station, boiling water to supply compressed steam [5] that may drive a turbine [6] which may be used to generate electricity [7] which we may then use in our homes to heat/light/move/cook or perhaps to recharge our mobile phone [3]. That energy will then be used to transmit microwaves when you make a call [2] which will mostly dissipate into the environment heating it (very) slightly [4]. Eventually the warmed earth radiates [2] this excess of heat off into the void where perhaps it will have another life…

This short story is testament to an enormous quantity of learning by our species, but there are some clear exclusions to be read into the story:

  • Energy fields (auras) or the energy lines in the body that conduct the “chi” (or life force) of Asian medical tradition
  • Energy lines on the Earth (aka Ley lines)
  • Negative or positive energy (as in positive or negative “vibes”)

These energy currencies relate to theories and beliefs that science has been unable to verify and thus they have no known “exchange rate”. Asking how many light bulbs can you power with your Chi is thus a nonsensical question, whereas it would not be for any scientifically supported form of energy. And since energy flows account for all actions in the universe, not being exchangeable would be rather limiting.

Where exactly is Energy kept?

This may sound like s strange question, we know Energy is kept in batteries, petrol tanks and chocolate chip cookies. But the question is, where exactly is it stored in those things?

Energy is stored in several ways:

  • as movement – any mass moving has energy by virtue of the movement, which is called Kinetic Energy
  • as matter – Einstein figured out that matter is just a form of energy, and the exchange rate is amazing – 1g = 90,000,000,000,000,000 joules (from E=mc^2)
  • as tension in force fields

That last one sounds a bit cryptic, but actually most of the energy we use is in this form –  petrol, food, batteries and even a raised hammer all store energy in what are essentially compressed (or stretched springs).

What is a force field? Why on earth did I have to bring that up?

All of space (even the interstellar vacuum) is permeated by force fields. The one we all know best is gravity – we know that if we lift a weight, we have to exert effort and that effort is then stored in that weight and can be recovered later by dropping it on your foot.

Gravity is only one of several force fields known to science. Magnetic fields are very similar – it takes energy to pull a magnet off the fridge , and so it is actually an energy store when kept away from the fridge.

The next force field is that created by electric charge (the electric field). For many years this was though to be a field all on its own, but a chap called Maxwell realised that electric fields and magnetic fields are in some senses two sides of the same coin, so physicists now talk of ‘electromagnetic’ fields. It turns out that electric energy (such as that stored in a capacitor) consists of tensions in this field, much like a raised weight is a tension in a gravity field. Perhaps surprisingly, light (as well as radio waves, microwaves and x-rays) are also energy stored in fluctuations of an energy field.

Much chemical energy is also stored in electric fields – for example, most atoms consist of positively charged nuclei and negatively charged electrons, and the further apart they are kept, the more energy they hold, just liked raised weights. As an electron is allowed to get closer to the nucleus, energy is released (generally as radiation, such as light – thus hot things glow).

The least well known force field is the strong ‘nuclear’ force. This is the forces that holds the subatomic particles (protons) together in the nucleus of atoms. Since the protons are all positively charged, they should want to repel each other, but something is keeping them at bay, and so physicists have inferred this force field must exist. It turns out their theory holds water, because if you can drag these protons a little bit apart, they will suddenly fly off with gusto. The strong nuclear force turns out to be bloody strong, but only works over a tiny distance. It rarely affects us as we rarely store energy with this energy field.

Now we understand force fields we can look at how molecules (petrol, oxygen, chocolate) store energy. All molecules are made of atoms connected to one other via various ‘bonds’ and these bonds are like springs. Different types of molecules have different amount of tension in these bonds – it turns out coal molecules, created millions of years ago with energy from the sun, are crammed full of tense bonds that are dying to re-arrnage to more relaxed configurations, which is exactly what happens when we apply oxygen and the little heat to start the reaction.

The complexity of the tensions in molecules are perhaps the most amazing in nature, as it is their re-arrangements that fuel life as we know it.

What exactly is Heat then?

You may have noticed that I did not include heat as a form of energy store above. But surely hot things are an energy store?

Yes, they are, but heat is actually just a sort of illusion. We use heat as a catch all term to describe the kinetic energy of the molecules and atoms. If you have a bottle of air, the temperature of the air is a direct consequence of the average speed of the molecules of gas jetting around bashing into one another.

As you heat the air, you are actually just increasing the speed of particles. If you compress the air, you may not increase their speed, but you will have more particles in the same volume, which also ‘feels’ hotter.

Solids are a little different – the atoms and molecules in solids do not have the freedom to fly around, so instead, they vibrate. It is like each molecule is constrained by elastic bands pulling in all directions. If the molecule is still, it is cold, but if it is bouncing around like a pinball, then it has kinetic energy, and feels hotter.

You can see from this viewpoint, that to talk of the temperature of an atom, or of a vacuum, is meaningless, because temperature is a macroscopic property of matter. On the other hand, you could technically argue that a flying bullet is red hot because it has so much kinetic energy…

Is Energy Reusable?

We as a species, have learned how to tap into flows of energy to get them to do our bidding. So big question: Will we use it all up?

Scientists have found that energy is pretty much indestructable – it is never “used-up”, it merely flows from one form into another. The problem is thus not that we will run out, but that we might foolishly convert it all into some unusable form.

Electricity is an example of really useful energy – we have machines that convert electricity into almost anything, whereas heat is only useful if you are cold, and light is only useful if you are in the dark.

Engineers also talk about the quality (or grade) of energy. An engineer would always prefer 1 litre of water 70 degrees warmer than room temperature, than 70 litres of water 1 degree warmer, even though these contain roughly the same embodied energy. You can use the hot water to boil an egg, or make tea, or you could mix it with 69 litres of room temperature water to heat it all by 1 degree. It is more flexible.

Unfortunately, most of the machines we use, turn good energy (electricity, petrol, light) into bad energy (usually “low grade heat”).

Why is low grade heat so bad? It turns out we have no decent machine to convert low grade heat into other forms of energy. In fact we cannot technically convert any forms of heat into energy unless we have something cold to hand which we are also willing to warm up; our machines can thus only extract energy by using hot an cold things together. A steam engine relies just as much on the environment that cools and condenses water vapour as it does on the coal its belly. Power stations rely on their cooling towers as much as their furnaces. It turns out that all our heat machines are stuck in this trap.

So, in summary, heat itself is not useful – it is temperature differences that we know how to harness, and the bigger the better.

This picture of energy lets us think differently about how we interact with energy. We have learned a few key facts:

  1. Energy is not destroyed, and cannot be totally used up – this should give us hope
  2. Energy is harnessed to do our dirty work, but tends to end up stuck in some ‘hard to use’ form

So all we need to do to save ourselves is:

  1. Re-use the same energy over and over
  2. by finding some way to extract energy from low grade heat

Alas, this is a harder nut to crack than fission power, so I am not holding my breath. It turns out that there is another annoying universal law that says that every time energy flows, it will somehow become less useful, like water running downhill. This is because energy can only flow one way: from something hot to something cold – thus once something hot and something cold meet and the temperature evens out, you have forever lost the useful energy you had.

It is as if we had a mountain range and were using avalanches to drive our engines. Not only will our mountains get shorter over time but our valleys will fill up too, and soon we will live on a flat plane and our engines will be silent.

The Big Picture

So the useful energy in the universe is being used up. Should we worry?

Yes and no.

Yes, you should worry because locally we are running out of easy sources of energy and will now have to start using sustainable ones. If we do not ramp up fast enough we will have catastrophic shortages.

No, should should no worry that we will run out, because there are sustainable sources – the sun pumps out so much more than we use, it is virtually limitless.

Oh, and yes again – because burning everything is messing up the chemistry of the atmosphere, which is also likely to cause catastrophe. Good news is that the solution to this is the same – most renewable energy sources do not have this unhappy side effect.

Oh, and in the really long term, yes we should worry again. All the energy in the universe will eventually convert to heat, and the heat will probably spread evenly throughout the universe, and even though all the energy will still be present and accounted for, it would be impossible to use and the universe would basically stop. Pretty dismal, but this is what many physicists believe: we all exist in the eddy currents of heat flows as the universe gradually heads for a luke-warm, and dead, equilibrium.

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Ok, so it was longer than a page, so sue me. If you liked this article, my first in a series on energy conservation, you might like my series on efficient motoring.

Please leave a comment, I seem to have very clued-up readers and always love know what you think!

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§ Footnotes:

[1] Matter is energy according the Einstein and the quantity relates to mass according to E=mc^2 (c is a constant equal to the speed of light).

[2] Radiation (like sunlight) is a flow of energy, and energy content relates the frequency according to E=hf (h is the Planck constant).

[3] Chemical energy – the most complex energy, a mixture of different tensions in nuclear and electromagnetic force fields.

[4] Thermal (heat) energy- this is really just a sneaky form of kinetic energy [6 below] – small particles moving and vibrating fast are sensed by us as heat.

[5] Compression (or tension) energy – while compressed air is again a sneaky form of kinetic energy [6], a compressed spring is different – it’s energy is more like chemical energy and is stored by creating tension in the force fields present in nature (gravity, electromagnetism and nuclear forces).

[6] Kinetic (movement) energy

[7] Electrical energy – this energy, like a compressed spring, is stored as stress in force fields, in this case electromagnetic force-fields.

Strange small things

Photography, Science, , , , , ,

I thought it may interest someone out there in cyberspace to see some of the weird things I have made in the lab, mostly by accident, and of no apparent value.  PS any apparent value that may emerge will belong to my employer anyway :).

Anyway, I must thank them (I have a very nice job), and team at the IAC at the University of Bristol, for their help taking these shots, particularly those where we have cut into the material, which was done with a beam of Gallium ions. Pretty neat hey?

Thanks,
Jarrod

Home made fly ash

This looks like fly ash, but was an accidental byproduct of recent research

Microsponge

Another accidental byproduct. Alas, the 'intended' products are just as cool, but are all hush-hush, top-secret, I could tell you but then I would have to kill you type things 🙂

Strange Section

Don't ask me. I may have made it, but I don't have a clue what it is.

House of cards

I love this one. It involved liquid nitrogen. Nuff said!

house of cards section

Here we took a cut into the structure from the previous picture to learn more...

Does your company need a corporate scientist?

Science, Science communication, The scientific method, , , , , , , , ,

Question: what is the point of having a scientific advisor?

We know the scientist type – they are pedantic, idealistic, inflexible – and socially challenged.

They are generally unable to do business in ‘the real world’. So why would you want one on the team?

We all know that business has some hard rules – the machines need to work and the numbers need to add up – but it is also an art – it is about people, about relationships, deals, loyalties, reputations. It takes care and passion. It is often irrational and is generally completely unpredictable.

So if it cannot be modelled and reduced to equations, why would you want an irritating pedant on the team?

Because in a complex world, the truth is worth its weight in gold.

A scientist’s job, is to use his or her training to filter out emotions, wishful thinking, bias and noise and identify what is true.

Just as every salesperson has their patter, every ceo will have their ‘summary’ for the board – and what they say will be wilfully spun. However, so long as they themselves know the basic truth, they will still be able to act wisely. They will also be able to maintain credibility pinning their spin on little nuggets of purest ‘truth’.

A world without a constant return to rational analysis will eventually wind up so twisted (the proverbial tangled web) that we will get entire businesses built on air.

Ok, so maybe we need someone to provide the boss with the unvarnished truth. What they then do with it then, well that’s business!

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Aside for accountants: To be fair, accountants are also supposed to do this, but I would argue that only a true scientist will (probably through a mental fault) put truth first. Note that I am not saying scientists are more honest than other people – they lie and cheat too, it’s a desire to find the truth that I’m talking out, which is no guarantee of a desire to speak it.

Confessions of Scientific Atheist

Atheism, Evolution, Philosophy, Psychology, Science, Science communication, Skepticism, , , , , , , , , ,

The Evolutionary theory of Natural Selection makes extraordinary claims. It explains the ability of creatures to convert sunlight to useful energy, to spin silk, to metabolise sulfurous rock – and much more besides.

Such amazing feats in nature require an amazing explanation. The existence of a God is very helpful in this regard; after all, humans have designed diesel cars and digital computers, so why couldn’t an entity with God’s power and talent create all the nature we see?

The trouble many people have with Natural Selection, is that while it can clearly explain some biology, using it to explain away practically all biology (and psychology, language, culture, etc.)  is an extrapolation – and a big one at that.

Why do scientists allow such an extrapolation? Surely this is arrogance?

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Thinking about this, I have an proposition…

If you come from the premise that there is nothing outside of nature (see my recent post), then it comes easily. If the God option is written off a priori, we have no other logical option than to expect that the gaps in our knowledge of evolution will be filled in eventually. This allows us to sleep at night with the extraordinary.

If you start from the premise that there is a God, then this will strike you are arrogant.

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The constant supply of greater details, filling in the gaps, gives encouragement to those who feel the theory is right (see God of the Gaps). It’s a bit like looking for Nessy – we can’t do a Star-Trek style ‘scan for lifeforms’ to be sure she does not exist, but the more we search the less likely she is to exist.

Of course, while evolution explaining away the wondrous variety in life does not prove there is no God, it sure makes God less necessary, and less necessarily capable.

Overlapping Magisteria

Atheism, Cosmology, Evolution, Philosophy, Science, Skepticism, , , , , , , , , , , , ,

Those who say science and religion are mutually exclusive are working from the philosophical premise that there can be something outside of nature.

Those who claim that religion can be scientifically investigated, come from the philosophical premise that there is nothing outside of nature.

As neither position is superior one cannot use logic to assign greater truth.

However, the claim that there is anything beyond nature (i.e. supernatural) is the more extraordinary claim, and thus carries with it the onus to justify and explain how to reach this conclusion.

The futility of being outside of nature:

If religion is truly outside of nature it can have no measurable effect on it. If it has no measurable effect then, even if existant, it would be fair to say it couldn’t be detected by science – but then neither could it be detected by the clergy.

Thus in a non-overlapping model, the benefits of a benevolent God, such as good crops, good weather, good luck, healing or charity are impossible, as they are generally detectable.

I guess you could argue that God goes to the trouble to disguise the causes for His blessings, but why is he so afraid to show it was the result of your good faith? This argument gets a little stretched once the solutions to that are proposed. It is similar to the argument that God planted the fossils in the order of their evolutionary development to fool us into thinking that life evolved…

The ref’s word is the law: pragmatism in science and the legal system

Science, Sports, , , , , , , , , , , , , ,

The Silent Contract

If you have ever played a sport competitively, there is good chance you have experienced a blatant error by the referee. If you are anything like me, and if the game is balanced on a knife edge, there is a good chance your blood pressure shot right up and you had some kind words to say about the ref’s eyesight and quite possibly the ref’s mother too.

And if you are like me you would look back later and realise you were somewhat out of order. It was, after all, at worst an error, and no ref is perfect.

However, in those moments of blind frustration,  that rule: “the ref’s word is final” seems so wrong. In big-brother/1984 style, once the ref says it was a foul, it was a foul and unless he changes his mind within a few seconds it will be forever recorded in history as a foul. The real true events become an irrelevant fantasy.

This policy clearly does not serve the ‘truth’, so why has it developed in so many sports?

Most footballers understand why – and most judges understand why.

Let us consider what would happen if the ref’s word were not final.

Imagine a system of democratic debate and judgement over all close-calls at a sports event. Recall that all contenders and most of the audience are highly partisan. It would not be football, it would be a debate. It is obvious you need someone impartial, and you need something quick.

So what actually happens is that all stakeholders enter a silent contract to accept the ref’s errors in order to keep the game lively.

Implications in Law

So we have an example where we in society are willing to accept that the truth is not the priority. I am OK with this on the football field, but this type of pragmatism is actually used every day in the legal system, which is rather scary to me.

There is a lot in common between a ref and a judge, or indeed a jury. It falls on them to decide the official version of truth based upon the available evidence.

However, because the consequences of legal judgement are routinely more extreme than a free-kick, a more considered system usually develops. In most western courts, there is now a ‘threshold’ (called ‘reasonable doubt’ in the US) beyond which ‘the probable” becomes ‘the fact’. If this sounds rather crude, its because it is – they are saying that after they look at the evidence, and place the judgement on a scale of probability (0-100%) that they will set a number, above which the person is guilty and below which they are not – giving our grey world a little more contrast.

If they set the threshold at 100%, to ensure that no innocent man is ever convicted, you would convict no one. If they lower it to get more practical conviction rates, they will soon start to convict the innocent. Thus a compromise needs to be reached – the exact level will be a moving feast, but will generally reflect the culture and the Zeitgeist.

The Alternative…

Who else has has to make a call about truth?

Scientists are also trying to discern ‘truth’ – about magnetism, about cellular function, about  black holes, well about most everything really.

Yes, they do use pragmatism – we, for example, continue to use Newton’s Laws in most calculations because we know they work well enough for most practical purposes. We also continue to build on theories that have inherent contradictions (meaning that are probably flawed), because history has shown that such pragmatism still  moves us forward and is better than getting ‘stuck’. Yes, it does lead to some waste, some researcher’s entire lives are built on earlier mistakes that were ‘pragmatically’ ignored (think of homeopathy).

However, in the end, the scientist has to keep record of all pragmatism and return to it and root it out, because in science, the truth is the target, and no compromise can be left on the books.

This raises an interesting tension when a scientist is brought into legal proceedings to provide ‘opinion’. Judges (and politicians) mistakenly think that science deals in facts (not probabilities), and would also ask a scientist to make a pragmatic call ‘yes, this is the suspect’s DNA’. A good scientist would leave judgement to the judge and sprinkle their statements liberally with the word ‘probability’.

But can a legal system make judgements with probabilities? Without thresholds and verdicts? Could we dole out punishment in proportion to the probability of guilt? Could we punish several people for one crime if we know one of them did it? I don’t know if we could.

Has such a system cropped up anywhere? I don’t know if it has.

Open Verdict

So science can leave matters undecided on the basis that more evidence may come, but science too, from time to time, may benefit from a little pragmatism – because just as in the law-courts, we have the power to set potential killers loose with our inability to be decisive. Think of  two words: ‘global’ and ‘warming’.