Can Physics Predict Evolution? - Assembly Theory Explained

what if life is all around us in the universe but we just don't see it because we're looking for the wrong signals the signs of earthlike life not one of the potentially Endless Sea of possibilities of how life could have formed in other parts of the cosmos A new Theory called assembly Theory aims to give structure and even predict the complexity of how these life forms may have evolved that look different to life on Earth some people are even calling it a new law of nature can this Theory tell us how and why we are here and more importantly has it reduced the meaning of life down to just some mathematics I contacted one of the lead authors of this breakthrough Theory to find out more so let's do a deep dive into assembly Theory but first I have to thank today's sponsor who makes these sorts of Deep dive episodes possible Babble I can talk to a computer in seven different languages but I can talk to human beings in only one and that is non Accolade that I am proud of so I started trying to learn a language multiple times over the past year nothing is really stuck I started using Babble recently and I've actually really enjoyed it Mio Dr Ben lessons are designed by real language teachers and it focuses on teaching you to have real world conversations it's scientifically backed and you'll learn the basics of how to speak a language in about 3 weeks whether it's for travel professional development or to become less of a computer if you are interested in giving Babel a shot I highly recommend it check out the link down below to get 60% off your subscription in Babel's Black Friday sale thank you Babel for keeping science content free on the internet now back to the video in imagine any object it is possible to break it down to the molecular level to the elementary building blocks of bonds that tie atoms together but how would you do the reverse to explore those possibilities you could map the steps those molecular building blocks could be assembled into first as small functional units and then how those units could then be assembled into more complicated ones and step by step across all possible configurations until ultimately you had your object but also you would have an infinite sea of other options most most of them probably not very useful we call this a phase space a mathematical concept used in the study of dynamic systems to represent all possible states of a system the journey to reduce that object the number of steps in that process is a challenge for the universe in physics and chemistry the only way we have to create more complicated objects is through random processes taking even a modestly small number of building blocks St materials and having Randomness over time as your only Force driving creation has very quickly a dauntingly huge phase space of what is possible to create so why with only Randomness driving the process do we see structure emerging so reliably going from carboncarbon bonds to human beings is statistically impossible and yet here we are this slightly daunting looking equation is the standard model it predicts everything that we know about the laws of the universe but it does not contain an explanation for why this complexity emerges at least that's what Sarah Walker and Lee Cronin lead authors of assembly theory suggest assembly theory is meant merely to help us at the very basic level determine if an object has been produced by the process of selection and evolution but when we realize we could identify things using assembly Theory this is when things got super interesting we realized there was a much bigger framework that we could use really something that helps us to tell the difference between random and non-random processes which is a I think quite a large Holy Grail actually in complex Theory there are lots of theories of complexity already proposed by many people of varying levels of credibility what is interesting I think about assembly theory is that they have really tried to make it mathematically well defined it is contained in this short formula a sum over all possible Arrangements of a system n combining how complicated they are to assemble a their assembly index multiplied with how many copies n i are seen over the possible sum of options NT a lot of people said this theory is just simple yep it's kind of cool it's simple so let's let's lay it out assembly is about um objects have a that you can find in identical copies and being able to work out if those objects are complex or not and then you can then use a theory and it's super simple but what I did is I put an a copy number is NI I minus one over NT and if copy number is one 1 - 1 is zero and that drops the entire assemblin of the equation to zero because you can't tell the difference between an infinitely complex object and and a random object the short mathematical formula as strange as it seems according to assembly Theory contains life itself but what exactly does that mean if the shortest path to creating an object involves a sufficiently large number of steps because of the combinatorial space of possibilities getting exponentially large it would indicate that you require something more than just randomness for the object to exist an outside force or a grand design a machine or a system capable of storing information the frequency of that object's occurrence also has to be taken into account highly complex objects can come into existence under purely random chance but a high number of Highly complex objects all appearing in the same place at the same time makes statistically unlikely become statistically impossible unless as we said before there is some driving force guiding the design and now this is kind of a weird thing for a physicist to say because it sounds like I'm about to introduce divine intervention or the fact that the universe is just a simulation run on a computer outside the universe which is an interesting topic but one for another video if you're interested luckily this Theory doesn't require either of those the answer to how this is possible is life but just because something is very well mathematically defined doesn't mean it's true so how do we see if assembly Theory really holds water take something like the banck tasy Paradox formulated by polish mathematicians Steven banck and Alfred tasi in 1924 this is a result in the realm of geometric set theory which deals with infinite set problems it states that it is possible to take a solid ball in three-dimensional space separate it into a finite number of non-overlapping pieces and using only rotations and translations reassemble those pieces into two solid balls identic to the original keep doing that process and that's infinite balls which is basically what it takes to propose such a theory but the math checks out but it doesn't correspond to a physical reality you can't actually do this with a real world object and hence might not be deemed useful or true in practical sense but maybe it's just not useful yet for centuries ukian geometry based on ukids postulates was seen as the only true geometry the fifth postulate often referred to as the parallel postulate states that if two lines are crossed by a third line and the internal angles add up to 180° the lines are parallel and will never converge it's hard to imagine a world where parallel lines aren't parallel but then in the 19th century mathematicians started exploring with geometries where ukids fifth postulate didn't hold culminating with the Advent of Einstein and his theory of relativity the non-clean geometry suddenly found a central role in describing the curvature of SpaceTime and how the universe behaves non- ukian geometry turned out to be both mathema ically valid and well- defined and practical in a way that produces some fundamental insights about how the universes that are hard to come up with without the mass to talk about them but does assembly Theory give us that same advantage in detecting life or understanding the universe entropy or the second law of thermodynamics states that all objects in the universe are governed by moving from order to disorder increasing in Randomness over time gradually losing energy until the ultimate heat death of the universe the complexity of life stands in stark contrast to this theory if a universal law of physics is Randomness always increases then how do we reliably get the processes of life well entropy requires you to label States the starting State and the ending State and in fact it's kind of odd right if you if someone gives you a sequence of events and you don't know where the time is you actually have to guess where the start and the end is to know whether entropy is increased or decreased and we know what the we know what the second law says but um I think there's something rather biased about the way the user interacts with the universe entropy whereas assembly doesn't care about that assembly just says let's let's ignore the Dynamics for a second take a snapshot and then come to a view about what that means life according to assembly theory is the capacity for memory specifically chemical memory stored in DNA and genes and grants the ability to repeatedly produce a complexity of object that otherwise should be statistically impossible I and I think that that's a very interesting way of understanding complexity a kind of punctuated equilibrium we see in biology but it looks like we might be get punctuated equilibrium before biology now that is a very functional and I think quite cold definition of life but that is mathematicians for you but the authors in too one step further and Define what complexity is in terms of Life anything with an assembly index over 15 is so complex and unlikely that random processes alone they say could not have produced it here is where life must have kicked in if the complexity to build something is above 15 Steps the randomness that could have driven this Creation in the first place also very likely would then destroy it but if a random process can evolve a way of storing how to build objects up to a certain complexity then it can start to produce many of these hard-to-produce components quite easily this creates a large supply of in increased complexity starting materials that further random processes and further random encoding can continue to evolve on over multiple Millennia of this simple bottomup assembly approach you can eventually realize the full complexity of humanity and Life as We Know It And from this definition we get a very discrete understanding of what an object produced by life might look like keep in mind that doesn't mean that the object is alive itself just that life was needed in order to create the object life and life derived of Deep related okay I mean I am um I am life derived I'm probably not formally alive unless I've had kids I have two kids so maybe I was alive once I think life probably is like Consciousness in a way it's kind of it's it's weaker than we think but life derived is a bit like um abstraction it does exist assembly Theory tells you if something is a product of an evolutionary process or not uh so a mouse or a computer or you know eBook reader is life derived and the product of evolution not directly but indirectly a virus for instance is life derived and the product of evolution now here's a cool thing people will say ah is a virus alive or dead mule alive or dead right mule can't self-replicate it's they they're they're sterile right but they are product of two other species coming together producing the mule por and mule is alive metabolically but it's not really alive assembly Theory says we can tell the difference of something is the product of selection or not we can't NE say how deep but my intuition is the more the larger the assembly the more you are from technology and there is a fresh hold where you look like you're from biology and of course biology is much higher it's got all this extra intricate stuff going on so the complexity of biology is a bit higher than the molecules that you can use to are say that are markers of the fact that biology was there but that's really cool because that means signatures of Life are easier to find and therefore spot skepticism of evolution often stems from the feeling that it can't be true that the only thing driving the creation of life is Randomness how through random processes alone do you go from chemical soup to human being the principles of evolution are simple and concrete but that doesn't mean that they're easy to visualize record or understand Evolution requires three things Randomness which physics supplies for us in the atomic and molecular motions of everything in the universe a selective pressure otherwise known as natural selection which removes things that don't work well either by making a less attractive to mate with or by getting us eaten by lions and finally the ability to inherit the last generation's Designs For Better or Worse which is done through the mechanism of DNA assembly theory of course supports all of these points but it also brings greater Clarity to the stepwise mechanism of The evolutionary process adding complexity is hard the only way to do it reliably is to build systems that allow you to benefit from reproducible semi complicated designs that then have the ability to make more complex designs in turn that makes the steps from chemical soup to self-replicating molecules to self-replicating molecules that do something useful to early cellular processes much more quantifiable basically evolution is a tendency it hasn't been precisely formulated beyond what Darwin the price equations and so on and don't get me wrong evolution is correct it is the best scientific theory we have but assembly allows you to frame it slightly differently so we can reconcile the universe initial conditions we don't know where Evolution comes from to a universe that Evolution and life exist in so it not only Bridge the dead to The Living World it will also help us to understand evolutionary trajectories in the future most of the effort in The evolutionary process isn't to go from ape to man but to go from goo to goo that is useful once you get to the cellular level things are ready to start to take off and that's because cells by Design Prime for complexity in evolution and limit the chaos of the surrounding Universe they try to let in only things that are good for the cell and good for life and keep out things bad for Life by only letting in the right starting materials and by having DNA and DNA repairing structures built up in complexity and capability over millions and millions of years every time you innovate in a commentarial space you get to an island of stability which allows you to then launch again into another coment torial space which is potentially even bigger but your kind of more constrained by your past what this does is reduce the field of possible options up until a point and so confine Evolution to still random but functional building on top of this stability this process in early life which I'm going to call cells but cells potentially is a few steps Beyond this complexity that is necessary allows the copy number of these objects to become very large from the mathematics of assembly Theory the more copies of an object you have the easier it becomes through random processes to add complexity to that object object so the cell becomes an engine of exploring what is chemically or evolutionarily possible and to clarify there I don't think that is unexplained by the theory of evolution as it sounds but it does give it an added piece of mathematical definition this is the process of evolution put down in simple inevitable mathematics but now that we have it what do we do with [Music] it we started this discussion with the idea that maybe life is out there we just don't recognize it we want to ask the question what is how common is life in the universe what regions of the universe are uniquely able to generate complexity and and complexity is not the jup the storm on Jupiter that's complicated it's not complex what is the difference well complexity I would give is actually what assembly Theory finally does it actually starts to take the whole area of complexity and make it a little bit more unambiguous and OB objective people right now looking for oxygen and and you know methane and phosphine and things and saying whoa these are signatures of Life the problem is although the molecules might be associated with some living processes they are too simple for you to know the difference there could be physical processes that do it if we make the simple assumption that alien life forms will produce molecules with a chemical complexity similar to that of life on Earth does this give us the ability to look out of the universe and better see life where we previously saw in organic matter last April the juice probe a European Space Agency Mission commenced its journey to study Jupiter and its surrounding satellite moons one of Jupiter's four largest moons Europa features a vast saltwater ocean beneath its icy shell and is thought to be a top contender in the solar system for potential extraterrestrial life if on board was a method of determining the chemical composition of the material that the probe encounters there something like Mass spectroscopy that measures the bonds in a material then in theory the assembly number and concentration of these molecules could be taken into account to quantify the likelihood that life had produced them and that isn't actually as easy as it seems take a look at this these strange objects show evidence of complex structure occasional functional looking complexes patterns that we typically see only in biological systems on Earth but these are all pictures of the result of exposing metal salts to silicate Solutions called chemical Gardens in most chemistry textbooks complex structures resembling plant growth emerging purely due to precipitation reactions but absolutely not life an assembly Theory would corroborate that the assembly index of this is low it's a simple solution of metal salts maybe the copy count would be high but that would just tell us that this happens often not in this instance that life is steering its hand let's look at another example the sort of thing that maybe you might see in any biology lab small spherical structures that grow divide and encapsulate other molecules mimicking some basic cellular behaviors but is this life it turns out these are just lipids long chains of fats that can spontaneously assemble and although we associate lipids and fats with biological life they can be produced without it and have in fact been found in interstellar clouds and on meteorites and these were potentially the sources that rained down on planets in the first place seeding them with the starting materials necessary for life but not necessarily produced by life in the first place because the complexity is low and the copy number is high we'd again probably say random processes can produce these though if we did find these on a planet we'd also probably be saying W this mechanism is a real Head Start in the process of creating life so even if it isn't here now it has a higher chance of being here in the future just because we found these and that is a gray area that I don't think assembly Theory covers off very well life useful complexes rather than life derived complexes kind of go unaccounted for similarly if we think about more straightforward examples if a creature on another planet took Stones off the beach and wrote s o in the sand that is a very low complexity of materials and a very low copy count number according to assembly Theory that's probably not life nothing to see here guys or if life on another planet beamed a radio signal of the last episode of Friends to us on Earth assembly Theory again doesn't quite model well for that clearly life derived evidence at least how I understand the paper as written and I'm very happy to be corrected here you can argue that assembly Theory deals predominantly with chemistry and I think that is a fair point to argue I think there is scope that maybe it usefully tells us about life in places we otherwise wouldn't expect but I'm not sure if that plays out practically strange complex compositions of matter that we find on different planets are strange complex compositions of matter that we find on different planets will definitely want to determine their origin regardless not simply understand their assembly index from what I've looked at assembly theory is interesting I don't think it's perfect but it targets a gray space less Quantified by physics and biology and I think that has Merit what I think is most interesting is that it gives us such a cold definition of life life is an emergent property that starts at the ability to reproduce some level of complexity then extended over time it can turn stars and dust into people it's still the mechanically random process that physics says it is but within it are islands of complexity where valuable information is stored in chemical form to increase the reproducibility of that complexity that doesn't reduce its value in fact life now by this definition is a fight to fulfill the impossible that is self-actualized out of the stter materials of the cosmos the thing that's super striking is it appears that life has appeared through the medium the substrate of chemistry chemical bonds hasn't occurred in gluons or neutrons or whatever it is has occurred at the level of bonds because you can get heterogenity that is chains of molecules that are different to give you unique identities and there seems to be something in that commentor space But it's just the beginning of the journey right I've got no clue what's going to happen next it's uh literally the nice thing about the way we've done an assembly theory is we've really being very honest and open about it talking to people it obviously it's got lots of discussion I don't know if assembly theory is important or whatever it's certainly interesting and getting people thinking in a new way and that's what more can you want from a scientific theory [Music]

Channel: Dr Ben Miles

Views: 158,806

Keywords: science, future, breakthrough

Id: w9EUGVsKqdU

Length: 21min 32sec (1292 seconds)

Published: Thu Nov 09 2023