What is NOT Random?

Key Takeaways

[Applause] what will happen tomorrow is not random in other words it's at least somewhat predictable I mean not entirely to be sure but some things will happen for certain and other things definitely won't for example the Sun will rise water will still freeze at zero degrees Celsius and you won't become Michael Stevens we know this because everything in the universe is made of twelve fundamental particles and they interact in four predictable ways what if I were able to determine the positions and velocities of every single one of these particles in the universe well you would be the intelligence envisioned by Laplace who thought if you could really figure out where everything is and how fast it's moving you would know the entire future of the universe because you know how every particle interacts with every other particle Wow so nothing would be unpredictable which means nothing would be random not even human behavior since we are made of the same fundamental particles as everything in the rest of the universe everything we will ever do or have ever done would be determined by the information in the state of the universe at any one time but what is information well it seems to be fundamentally about order the order of molecules in your DNA contained the information needed to make you it is the order of zeros and ones streaming through the internet that contain all the information required to play this video it is the order of letters that makes a word on the order of words that makes a sentence that carries information so fundamentally information seems to be about order regularity that is until you really think about it I mean does every letter of a word carry the same amount of information no I mean after a cue you know almost for certain that the next letter will be a u after a th there will probably be an e so these letters carry very little information because you could predict them beforehand they are redundant in fact the founder of information theory Claude Shannon estimated the redundancy of English at about 75% which is why we can make sense of things like this so English can be compressed because it is not random it has patterns similarly video is compressible because of its regularities in each frame the pixels of similar color cluster together Plus from frame to frame most of the pixels don't change so you only need to record the ones that do change you can take advantage of this technique to create some trippy effects known as data moshing it's the application of the movement data from one video to the pixels of another it also means that an average video can be compressed to just one thousandth of its original size but what is the most you can't compress something well anything that is not random any patterns or regularities can be reduced because they are predictable so you can continue shrinking a file down until what you're left with is totally random and that will contain all of the information of the original item but distilled pure information so pure information is randomness if you want to know how much information something contains you need to know how random it is and randomness is disorder what we also call entropy so information fundamentally is entropy this makes sense if you consider a string of binary digits for example this string is perfectly ordered it has very low entropy and it contains no information that's the state of an erased hard drive now this string contains slightly more information but again the regularities allow it to be easily compressed so the string that contains the maximum amount of information is just a random set of zeros and ones it has maximum entropy because it's totally disordered you could not predict any of those digits by looking at any of the other digits and if you wanted to send this information to someone you would have no other option but to send the whole string of digits there's no way to compress it but here's the thing about any object that contains maximum information us as human beings they carry no meaning for example a video containing maximum information we look like this it is just white noise the color of each pixel is independent of all the other pixels and they all change randomly this video could not be compressed because it's already totally random now a random sequence of DNA would not make an organism and a random string of letters does not generally make a word we are drawn to things that are neither perfectly ordered containing no information nor are they perfectly disordered containing maximum information somewhere in the middle we can recognize complex patterns and that is where we derive meaning in music poetry and ideas it is this search for meaning that leads us to propose scientific theories which if you think about it are really our way of compressing the universe for example general relativity our current theory of gravity compresses into one short equation everything from how an Apple falls to the earth to have a moon orbits the earth and all the planets orbit the Sun how the Sun orbits a supermassive black hole at the centre of our galaxy how black holes form and behave and how the whole universe expands out from the Big Bang now that we have this theory the future is more predictable I mean we can predict eclipses thousands of years into the future so with all of our scientific theories does that mean that the universe is completely not random that it is perfectly predictable well let's assume for a second that Laplace was right and that knowing the state of the universe at any one time means you also know its state at every other time as well well that would mean that the information in our universe would be constant but if information is entropy that would mean the entropy of the universe is also constant and that does not appear to be the universe that we live in the second law of thermodynamics states that entropy in the universe increases with time or in other words things don't stir themselves apart but if entropy is going up that the information in our universe is constantly increasing that makes sense because it would take more information to specify the state of the universe now then right after the Big Bang so where is this new information coming from my best bet is quantum mechanics quantum mechanics describes how the twelve fundamental particles behave and as spectacularly successful as it is it is only a probabilistic theory meaning that you cannot predict with absolute certainty where an electrons say will be at some later time you can only calculate probabilities of where you are likely to find it so when you do interact with it and locate the electron at a particular point you have gained information you now know something that you couldn't have predicted with certainty beforehand this drove Einstein crazy he said God does not play dice referring to this I mean he wished that we could compress our theory of quantum mechanics further so that we could really figure out where these particles were going to be but maybe the reason why we haven't been able to compress quantum mechanics further is because fundamentally it's random fundamentally new information is being generated every time a quantum event like that occurs in that case it could be these quantum measurements which are driving up the entropy of the universe they are creating new information all of the time and that means the disorder in our universe must go up this is what we observe as the second law of thermodynamics you know we often think about the second law as a curse as though everything which is ordered is going towards disorder but maybe I mean it's only in a universe where this law is obeyed that the truly unexpected can occur that the future can be actually undetermined for us really to have free will we need the second law of thermodynamics now you might think that these quantum events are too small to have any meaningful impact on the evolution of the universe but that is not true and that's because there are physical systems which are so dependent so sensitive to the initial conditions that any tiny change will end up making a big difference later down the track that's called chaos but it's also known as the butterfly effect so you and I could be such physical systems chaotic systems and our free will could come from quantum events in our brains so it looks as though we live in a universe where the future is yet to be determined that is to say it's at least somewhat random but Derek what is the most random thing possible in the universe you know it's such a good question I'm talking about it over on Vsauce you want to go find out about randomness with me let's go check it out all right and you can decide whether to click over or not oh that's nice [Music] [Applause] [Music]