“The ash of stellar alchemy had emerged into consciousness” — Carl Sagan
For those inclined, we all seek a holistic and complete narrative that explains nature. This need for a gestalt interpretation of our environment is the driver of our own general intelligence. This is the missing link in today’s AI systems. The most advanced AI systems (i.e. Deep Learning) are unable to construct layers of higher abstractions. This is despite being constructed of multiple layers that are intended to consolidate representation from one layer into another.
Here I put forward a narrative of why complex life emerges and why it is the same narrative as to why general cognition emerges. I am going to attempt a narrative that begins also with the early universe and builds up the principles of modularity as revealed by the evolving universe. I’ve discussed this idea previously in “Cooperation, Competition and the Emergence of Modularity”, but there is an alluring appeal of a narrative that begins from the beginning of time and works its way to the present self-aware universe.
Here is my narrative.
In the beginning of our universe everything was bound together and then in a single big bang, everything was instantly unbound. The initial conditions are unknown to current physics. The universe subsequently evolved into particles that were distinct (i.e. fermions). In addition, messengers (i.e. bosons) would bind them together but preserve their distinction.
In this universe there was light, manifesting itself as the photon the messenger of the electromagnetic force. There were other messengers, like the gluon, the messenger of the strong force. Gluons bound Baryons (i.e. protons and neutrons) in the nucleus of atoms together. Photons bound the nucleus with a charged lepton (i.e. electrons). There were forces in this universe that bound it all together (bosons) and there was stuff to be bound (fermions). Thus a primitive kind of modularity has always existed. The first principle of modularity: There is something that binds and something to be bound. Binding creates identity and interaction.
This unbound universe begat time. The universe, that was originally bound, has always remained connected after the Big Bang. The Holographic principle and quantum entanglement reveal this connection. It is through this entanglement that the entropic force of gravity arises. Gravity gives spacetime its curvature and thus any shape, absent uniformity, time becomes observable. Time is a consequence of entropy and entropy is how we are made aware of time. The second principle of modularity: The universe evolves in the direction of higher entropy.
Gravity is the force that always binds particles with mass together (it is conjectured that mass is bound by the Higgs’ boson). Through this force, stars are born and galaxies are formed. Stars consolidate through gravity and ignite with energy as a result of the strong nuclear force. This creates the plasma that is a catalyst for the creation of heavier elements. The third principle of modularity: A medium with fluid characteristics drive experimentation and thus innovation.
Eventually some stars with sufficient mass collapse and explode into a supernova. This is a result of the competition between gravity and nuclear forces. This supernova explosion further fuses additional heavier atoms and all these newer elements are scattered into the cosmos with the star’s destruction. The byproducts of a supernova are the elements of the periodic table. It is what forms the planets and the earth we live in. All life is a consequence of stars that die. We are ‘star stuff’ according to Carl Sagan. Destruction leads to creation. The fourth principle of modularity: Competitive forces leads to destruction that then leads to new composite creations.
So far, I’ve written only about forces that bind. That is gravity, the strong force and half of the electromagnetic force. There are forces that also repel, different charges repel and the weak force leads to radioactive decay of atoms. It can be argued that a universe such as ours can exist without the weak force. However, the effect of like charges repelling is essential for the richness of interaction in the universe. Not everything binds together, there exist constraints that prevent binding. Heavier elements are restricted to the combinations that is possible in quantum mechanics. The fifth principle of modularity: Binding is selective and drives the fitness of a context.
The stuff of stars, members of the periodic table of elements, creates new ways of interaction between different elements. The combination of elements into molecules is a consequence of quantum mechanics. The periodic table of elements is structured to reflect the atom’s outermost valence shell that influences chemical bonds. The sixth principle of modularity: Composite components leads to richer interactions and greater possibilities.
Chemistry leads to more complex compounds. Water, H2O is an example of a compound that has the emergent property that at a certain temperature exhibits itself as a liquid. Liquids form the environment that facilitates recombination. Here nature has rediscovered the liquid is found in the cores of stars. Fluidity is the substrate of experimentation and thus innovation. The fluidity of water creates the conditions for a marketplace of trade and interaction between complex compounds
Heavy elements that exhibit richer opportunities for interaction, participate more often as a constituent of complex compounds. Carbon and eventually Silicon, both group 6 elements in the periodic table, exhibit an intrinsic adaptivity that encourages the construction of more complex compounds. All of organic chemistry is a consequence of Carbon. Carbon can form four different bonds with other elements, enabling more interactions with other elements and itself to form a richer array of compounds. Stuff that is intrinsically adaptive just finds itself to be more prevalent simply because of probability (see: Dissipative Adaptation). The seventh principle of modularity: Intrinsic adaptivity leads to utility that leads to ubiquity.
Organic chemistry consists of molecules that can react in even more different ways than compounds. In the infographics below, each functional group is expected to react similarly. More complex molecules can consist of more than one of these groups and can thus interact in a manner that is a combinatorial explosion of these groups. Nature, in the form of organic chemistry, has again has recreated new ways of interacting and binding components.
This rich diversity in organic chemistry still doesn’t get you all the way to living things. Apparently, the basis of organic life on earth requires amino acids, the building blocks of all living organisms. The exact origin of how organic chemistry leads to amino acids is still subject to inquiry. Let us plug in a recent theory of how life came existence from organic matter. Jeremy England has a proposal known as “Dissipative Adaptation”, basically it explains how regularities of energy in the environment cause structures to form that are in harmony with these regularities. As Ilya Prigogine had proposed, a system is far from equilibrium self-organizes and develops order out of chaos. A more dynamic and richer form of memory (i.e. information storage) emerges. The eight principle of Modularity: Adaptive components reduce entropy by learning the regularities of the environment.
There are 20 of these amino acids with the average length of a protein being 200 amino acids in length. Thus, these proteins can be interpreted as a language with 20²⁰⁰ (i.e. 1.6x10²⁶⁰) different combinations. The age of the universe in nanoseconds is 4.34x10²⁶, so it is obvious that not all combinations of amino acids have been explored. It is unnecessary to search the entire space of possibilities to find an optimal configuration. The ninth principle of Modularity: Evolution requires only what is adjacently possible.
But what makes amino acids so valuable in the creation of life? It turns out that proteins have a recently discovered capability. Proteins are able to act in aggregate like liquids. Atoms required high energy plasma to drive innovation. Complex compounds require water to drive innovation. Proteins equivalently create their own fluid environment necessary to drive exchange and thus innovation.
The two other kinds of biomolecules that are found in life these are lipids and nucleic acid. Fatty lipids that form the membranes of cells. This is an extension of the first principle. There is always something that encapsulates and insulates an entity from its environment. The instructions for creating proteins (chains of amino acids) are encoded in nucleic acid in the form of DNA. Evolution discovers a mechanism to code an instruction set that transcends the lifespan of each individual life form. The tenth principle of Modularity: Robust error resistant encoding preserves learning across component life spans.
Previous to the evolution of DNA, permanence was a consequence of availability and adaptability. That is, what was more pervasive were entities that were simply less complex and intrinsically adaptable. Robust coding replicates more complex machines and potentially more adaptive machines. The more complex a machine, the less likely it can be preserved due to entropy. Over time, parts that require energy to sustain will eventually deteriorate. The more complex the system, the more likely that a wrench in the machinery renders the entire machinery inoperable. Complex life is unlikely without DNA encoding.
Nature will always favor simpler and robust machines, but DNA enables an alternative path that transcends probabilistic mechanisms to create complex life that is highly improbable. This remains a truism today even though we see only mostly complex life and technology in our daily lives. Microorganisms outnumber complex lifeforms on earth. The human body contains micro-organisms that outnumber human cells by 10 to 1. A 200-pound human carries around 2 to 6 pounds of bacteria that are essential to its health.
Thus with amino acids, lipids, and DNA we arrive a new set of mechanisms for fluidity, encapsulation, and preservation that existed in previous stages. Atoms combined in plasma, encapsulate via electromagnetic forces and preserve via the strong force. Molecules combine in water, encapsulate via carbon bonds and preserve through adaptive dissipation (i.e. external driving forces). At every level of evolutionary complexity, there is a medium for interaction, a boundary that mediates interaction and a mechanism that preserves identity. These three capabilities lead to a generative system that I label as Generative Modularity.
One of the great enigma’s of the study of life is how did amino acids, DNA and lipids all arise when each is dependent on each other. It’s a “chicken and the egg” problem. The key to unraveling this circular conundrum is in that a more primitive mechanism equivalent mechanism existed prior and was eventually made obsolete. Evolution does not need to keep around parts that do require anymore.
The Eukaryotic cell, the basis of all complex life, is a consequence of the symbiosis of other prokaryotic cells. The mitochondrion, the power plant, in a cell have their own DNA. This cooperative process (see: Endosymbiosis ) of assimilating separate life forms that have their own unique adaptive functionality is prevalent in biology. The eleventh principle of Modularity: Novel learning is gained by the symbiosis of complex behavior that is learned under different contexts.
This leads us to this general model of evolution:
where higher levels of modularity are created through competitive pressures that selectively discover fitness and consolidate capabilities through cooperative symbiosis. This is a narrative that is richer than the narrative of competition found in Darwin’s ‘natural selection’. Evolution requires selection for fitness as well as cooperation. Cooperation is, in fact, is a consequence of the adjacent possible. Cooperation requires the discovery of complementary and synergistic capabilities to bind with. It is in cooperation that evolution drives toward more complex life.
So far in this narrative, I reveal how the universe is evolving towards higher complexity, but I have not revealed any force that drives this universe towards higher complexity. There is a missing and mysterious actor in this narrative. The universe acts on always on the principle of least action. Given any context, the natural (and thus most probable) solution that will satisfy the boundary conditions will be the one that is less complex. If we interpret this principle in terms of models, this is Occam’s Razor in effect here. This is Solomonoff’s induction principle that demands a lower descriptive length for any program and thus less complexity. What is driving the higher complexity?
Let’s look at the universe before any supernova. That is a universe with just hydrogen atoms. Gravity as an entropic force creates a star that creates helium and given sufficient gravity, blows up to make heavier elements. How did this new universe exist that previously not have heavier elements? The constructive laws of the universe say nothing about the impossibility of heavier elements, even though such heavy elements did not exist previously. Certain configurations are stable (i.e. protons with neutrons) and certain more simple ones are not (i.e. just protons). There’s no law that more simple is more probable that more complex in every context. Rather, there will always exist configurations that are more complex and more stable than simple configurations. This is just a consequence of the original material you are gifted with. That is, evolution proceeds with what is adjacently possible and within that context, what is more, complex just happens to be what is possible and not some simpler thing that is impossible. The twelfth principle of modularity: Innovation is contextual, complex or simple solutions are driven by what is possible and not what is simple or optimal.
A common theme in evolution is this notion of constructivism. That is evolution proceeds in stages and is built from previous stages. Each new stage derives from the capabilities from the previous stage. However, the capabilities of the new stage are the emergent capabilities that did not exist previously. Surprisingly, abstract notions of modularity reveal themselves with each new stage. There are patterns of information modularity that repeat themselves as each new stage. There are patterns of information modularity that don’t exist in previous stages but become emergent with each new stage.
Now that we have arrived at the basic building blocks of life, I will discuss how this new self-replicating capability leads toward general intelligence.