The sixth breakthrough
Approximately 1 million years ago, with the emergence of the modern human brain, the 4-billion-year evolutionary story of humanity finally came to an end. Looking back, we can begin to paint a picture or construct a framework to showcase the formation process of the human brain and intelligence. We can integrate these stories into the framework of our first five breakthroughs.
The first breakthrough was turning: navigating by distinguishing between good and bad external stimuli to seek advantages and avoid disadvantages.
About 600 million years ago, coral-like animals with radially symmetric neurons gradually evolved into bilaterally symmetric animals. This bilaterally symmetric body structure simplified navigation decisions into binary turning choices. The neural network was integrated into the first brain, enabling signals with opposite valences to be integrated into a single turning decision. Neuromodulators such as dopamine and serotonin allowed continuous states to be repositioned more effectively and specific areas to be searched locally. Associative learning enabled these ancient worms to adjust the relative valences of various stimuli. In this earliest brain, the early emotional templates of animals emerged: pleasure, pain, satisfaction, and stress.
The second breakthrough was reinforcement: repeating behaviors that historically brought positive value and suppressing those that brought negative value through learning.
In the field of artificial intelligence, this can be regarded as a breakthrough in model-free reinforcement learning. Around 500 million years ago, a branch of an ancient bilaterally symmetric animal gradually evolved into the earliest vertebrates, which were most similar to modern fish, with the development of a spine, eyes, gills, and a heart. Their brains gradually formed the prototype of all modern vertebrate brains: the cerebral cortex is responsible for pattern recognition and constructing spatial maps, while the basal ganglia conducts trial-and-error learning. Both of these structures are built upon the remnants of the more ancient valence mechanism in the hypothalamus. This model-free reinforcement learning brought about a series of familiar intellectual and emotional characteristics: learning from absence, time perception, curiosity, fear, excitement, disappointment, and relief.
The third breakthrough was simulation: mentally simulating stimuli and behaviors.
Approximately 100 million years ago, in our approximately 4-inch-long mammalian ancestors, the cortical sub-regions of our vertebrate ancestors gradually evolved into the modern neocortex. This neocortex enabled animals to simulate reality internally, allowing them to show the basal ganglia what to do through imagination before taking actual action - that is, learning through imagination. These animals gradually developed the ability to plan, which allowed these small mammals to reenact past events (i.e., episodic memory) and consider different possibilities of past events (i.e., counterfactual learning). The subsequent evolution of the motor cortex enabled animals to plan not only the overall navigation route but also specific body movements, endowing these mammals with unique and efficient fine motor skills.
The fourth breakthrough was mentalizing: building a model of one's own mind. Around 10 to 30 million years ago, new regions evolved in the neocortex of early primates, building models of the old mammalian neocortex regions. This meant that these primates could not only simulate behaviors and stimuli (like early mammals) but also simulate their own mental states with different intentions and cognitions. These primates could then use this model to predict their future needs, understand the intentions and cognitions of others (i.e., theory of mind), and learn skills through observation.
The fifth breakthrough was language: through naming and grammar, language connects our internal simulations, allowing thoughts to accumulate across generations.
Each breakthrough was only possible on the basis of the previous ones. The emergence of the turning function was made possible by the evolution of neurons. Reinforcement learning was possible because it was built on the already evolved valence neurons; without valence signals, reinforcement learning could not begin. Simulation was possible because the trial-and-error learning mechanism in the basal ganglia already existed. Without the basal ganglia supporting trial-and-error learning, imagined simulations could not affect behavior. Due to the evolution of trial-and-error learning in vertebrates, vicarious trial-and-error behavior emerged in mammals. Mentalizing was possible because simulation preceded it. Mentalizing is simply simulating the older mammalian part of the neocortex, turning the same computational process inward. And language was possible because mentalizing preceded it. Without the ability to understand the intentions and cognitions within others' minds, we could not accurately judge how to effectively convey our own thoughts, let alone discern the true meaning behind others' words. Without the ability to infer others' cognitions and intentions, we could not participate in the crucial process of shared attention, which is necessary for teachers to point out learning objects to students.
To date, human history can be divided into two major chapters. The first is the evolutionary chapter, which tells how modern humans evolved from the original inanimate matter in the universe. The second is the cultural chapter, which describes how social modern humans gradually emerged and developed from biologically similar but culturally primitive ancestors around 100,000 years ago.
Although the evolutionary chapter spans billions of years, most of what we learn in history classes unfolds within the relatively short period of the cultural chapter - all civilizations, technologies, wars, discoveries, dramas, myths, heroes, and villains have all played out in this blink of an eye compared to the evolutionary chapter.
An individual Homo sapiens 100,000 years ago carried one of the most amazing wonders in the universe in her mind, a glorious achievement forged through more than 1 billion years (albeit unintentionally) of arduous evolution. She stood at the top of the food chain, wielded a spear, wore hand-woven clothing, tamed fire, and conquered countless beasts, effortlessly demonstrating numerous intellectual achievements. However, she had no idea where these mysterious abilities came from and could not foresee the grand, tragic, and miraculous journey that her Homo sapiens descendants would embark on.
Today, countless almost unimaginable events have converged to bring us to this moment: from the first bubbling cell emerging from a hydrothermal vent to the first predatory battle among single-celled organisms; from the birth of multicellular organisms to the differentiation of fungi and animals; from the emergence of the first neuron and reflex in ancestral corals to the birth of the first brain with valence, emotions, and associative learning ability in ancient bilaterally symmetric animals; from the rise of vertebrates to the mastery of time, space, patterns, and prediction; from the simulation ability born in the gasps of tiny mammals evading dinosaurs to the process of arboreal primates building political systems and mentalizing; from the birth of early human language to the gestation, adjustment, and destruction of countless ideas in the billions of language-capable human brains, all of this has spanned the past hundreds of thousands of years. The accumulation of these ideas has reached an astonishing level, enabling modern humans to type on computers, write, use mobile phones, cure diseases, and even create new artificial intelligence in their own image.
Evolution is still in full swing. We are at the beginning, not the end, of the story of intelligence. Life on Earth has only a 4-billion-year history, and our sun will not go out for another 7 billion years. Therefore, at least on Earth, life has about 7 billion years to explore new forms of biological intelligence. If the primitive molecules on Earth only took 4.5 billion years to evolve into the human brain, then what heights can intelligence reach in the next 7 billion years? Assuming that life can somehow leave the solar system or at least emerge independently in other parts of the universe, evolution will have even more time to work its magic: before the universe expands to the point where new stars can no longer form in 1 trillion years and before the last galaxy disintegrates in 1 quadrillion years, the time for evolution will be incredibly long. It's hard to imagine that our 14-billion-year-old universe is actually very young. If we compress the 1 quadrillion-year history of our universe into one year, we'll find that we are currently in the 7th minute of this year, not even at the dawn of the first day.
If our modern understanding of physics is correct, then in about 1 quadrillion years, when the last galaxy finally disintegrates, the universe will begin its slow, meaningless fading process and ultimately head towards the inevitable heat death. This is an unfortunate result of the irreversible trend of entropy increase, the primitive and irresistible force in the universe that the first self-replicating DNA molecules began to contend with 4 billion years ago. Through self-replication, DNA found a respite from entropy increase, existing in information rather than matter. All evolutionary innovations since the first strand of DNA have adhered to this spirit - the spirit of persistence, the spirit of fighting against entropy increase, and the spirit of refusing to fade into nothingness. In this great battle, the ideas passed down through language in human brains are the latest but not the last innovation of life. We still stand at the foot of the mountain, having only taken the fifth step on the long staircase leading somewhere.
Of course, we don't know what the sixth breakthrough will be, but it seems increasingly likely to be the emergence of superintelligence - the emergence of our descendants in silicon, realizing the transformation of the intelligent carrier from a biological medium to a digital one. In this new medium, the cognitive ability of a single intelligence will expand astronomically. The cognitive ability of the human brain is severely limited by factors such as the processing speed of neurons, the body's heat, and the maximum size the brain can reach in a carbon-based life form. The sixth breakthrough will be the moment when intelligence breaks free from these biological limitations. Silicon-based artificial intelligence can expand its processing power infinitely as needed.
In fact, as artificial intelligence can freely copy and reconfigure itself, individuality will lose its clear boundaries. As the biological mating mechanism is replaced by a new mechanism based on silicon for training machines and building new intelligent entities, the concept of parent-child relationship will also take on new meaning. Even evolution itself will be abandoned, at least in its well-known form. Intelligence will no longer be bound by the slow processes of genetic variation and natural selection but will be driven by more fundamental evolutionary principles, the purest principles of variation and selection - when artificial intelligence reconstructs itself, those that choose to support better survival characteristics will of course survive.
Whatever intelligent strategies evolve next will surely bear the mark of human intelligence. Although the basic medium of these super artificial intelligences has broken free from the biological limitations of the brain, these entities will inevitably be built on the foundation of the previous five breakthroughs. This is both because these five breakthroughs form the cornerstone of the intelligence of human creators (creators will inevitably leave their mark on their works) and because in the initial stage, these superintelligences will be designed to interact with humans, so they will be given a reproduction, at least a certain degree of mirror image, of human intelligence.
We stand on the brink of the sixth breakthrough in the history of human intelligence development, about to take control of the process of the origin of life and give birth to superintelligent artificial life forms. Standing on this brink, we face a very unscientific question, but in fact, this question is far more important than a scientific one: What should be the goal of humanity? This is not a question about truth but about values.
As we can see, past choices continue to have an impact over time. Therefore, how we answer this question will have a profound impact on countless generations. Will we successfully cross the galaxy, explore the hidden mysteries of the universe, create new intelligent life forms, unlock the secrets of the universe, discover new characteristics of consciousness, become more compassionate, and embark on unimaginable adventures? Or will we fail? Will the burdens of pride, hatred, fear, and tribalism left over from our evolutionary process tear us apart? Will we, like other evolutionary stages with tragic endings, just be a passing moment in the long river of history? Perhaps millions of years after the extinction of humanity, some species on Earth (perhaps bonobos, octopuses, dolphins, or jumping spiders) will try to climb this evolutionary mountain again. Perhaps they will find our fossils, just as we found dinosaur fossils, and guess what our lives were like, write books about our brains. Or, even more sadly, we humans may end this 4-billion-year experiment of life on Earth by destroying the Earth's climate or waging a nuclear war.
As we look forward to this new era, it is necessary for us to look back on that 1-billion-year-long journey and explore the mystery of the birth of our brains. As we gradually acquire god-like creative abilities, we should also draw wisdom from the "unconscious evolutionary process." The more deeply we understand our own minds, the more we can create artificial minds in our own image. At the same time, the more thoroughly we understand the formation process of the mind, the more wisely we can choose which intelligent characteristics to discard, which to retain, and which to improve.
We are the driving force behind this great transformation that has spanned 14 billion years. Whether we like it or not, the universe has placed the baton in our hands.
This article is from the WeChat official account “Tencent Research Institute” (ID: cyberlawrc). Author: Max Bennett. Republished by 36Kr with permission.