In the previous chapter we made an important distinction between universal and parochial features in evolution, and argued in passing that intelligence is a universal evolutionary strategy, likely to be found wherever life has taken sufficient hold. In this chapter we refine that theme by examining the evolution of intelligence on our own Earth.

You will have noticed that in the game tree of figure 14 there is a gap between top-down and bottom-up. How big is it?

It contains virtually the whole of the game tree.

There is a similar gap between what is accessible to top-down and bottom-up reductionist science. In this chapter we give this gap a name: Ant Country. The origins of the name lie in a simple mathematical system, Langton's ant, which we shortly introduce. We shall employ Langton's ant as a metaphor to open up the nature of simplicity, complexity, and the relationship between them. Langton's ant itself is an instance of ‘simplexity’, the tendency of a single, simple system of rules to generate highly complex behaviour, but it also leads to a more subtle concept, which in Collapse we called ‘complicity’.

‘It would be very singular,’ wrote Voltaire, ‘that all nature, all the planets, should obey eternal laws, and that there should be a little animal, five feet high, who, in contempt of these laws, could act as he pleased, solely according to his caprice.’ It is an eloquent statement of the problem of free will, and it is the place where our figments run slap up against reality, like the proverbial irresistible force meeting the immovable object. We have a distinct, overwhelming impression that we have a free choice concerning the actions that we take: free, that is, subject to the evident constraints of physical law. We cannot choose to float into the air, for example. Yet there is absolutely nothing in the inorganic world that possesses that kind of freedom.

To many people, science is seen as a source of certainty, a box full of answers that can be trotted out when dealing with life's many questions. Most working scientists, however, see their subject in a very different light: as a method for navigating effectively in an uncertain world. Whatever science may be, it is not just a matter of assembling ‘the facts’.

We have already offered you two versions of what happened during the evolution of life on Earth. We described the origins of life, the endless aeons when bacteria - many of them photosynthetic and emitting oxygen - were the dominant life-form, the development of eukaryote cells with nuclei, of multi-celled organisms including complex animals with brains, and the appearance of organisms that could learn.

The Ringmaster of the Zarathustran cruise-vessel Watcher-of-Moons lay back and tried to relax in a sensuous swaddle of preening-curd, only his eyes and beak projecting from the glutinous layers, giggling slightly whenever one of the nanotribbles that roamed the curd in search of tiny parasites and dirt particles encountered a sensitive patch of skin around the base of his funny-feathers.

His mind was troubled. It had been a strange voyage. Those extelligent ape-creatures with their overprivileged solo minds and their extraordinarily unoctimistic view of how the world worked were really disturbing. Always obsessed with the insides of things – no doubt a resurgence of their child-aspect in later life, the monkey curiosity that tried to find out how things worked by breaking them and seeing what they no longer did.

He expanded his neck-ruff, the Zarathustran equivalent of a sigh. The problem with preening-curd is that once you have opened a tuble you have to wallow for a full octad, and after a time preenwallow gets boring. Especially to a Ringmaster, who spends so much time making sense out of what everybody else is doing …. And this Ringmaster was subject to troubled thoughts, things he was having difficulty rationalising. He recalled that not an octuple of octoons away from him was an almost inexhaustible source of alien extelligence, refreshing even if naive. And once Hewer-of-wood had got the catalytic converter working again, Watcher-of-Moons would resume its voyage … For a moment he wondered which catalyst it was failing to convert, but he would only be able to explain that to everybody when Destroyer-of-facts had found out.

Isn't it strange that the animal we used to be developed into the creature that we now are? How – and why – did human intelligence and culture evolve? How did we evolve minds, philosophies and technologies? And now that we have them, where are they taking us?

The orthodox answer to these questions looks inside our brains to see what they are made of and how the various components operate. This leads to a story based upon DNA biochemistry, the evolution of nerve cells as pathways for sensory information, and their organisation into complex networks – brains – that can manipulate neural models of natural objects and processes. Mind is seen as a property of an unusual brain – complex enough to develop culture – but here the ‘reductionist’ story starts to lose its thread. Many people see mind as something that transcends ordinary matter altogether. Philosophers worry that the universe around us may be a figment of our own imagination.

In Figments of Reality we explore a very different, but complementary, theory: that minds and culture co-evolved within a wider context. Every step of our development is affected by our surroundings. Our minds are rooted in ordinary matter; they are complex processes – or complexes of processes – that happen in material brains. Our brains are linked to reality by their molecules; but they are also linked to reality on another level, their ability to model reality within themselves.

We end our journey through human mind and culture by trying to answer some of the questions that we raised in the opening chapter. How did such a peculiar animal as the human gain such a grip upon the planet? What is it that makes us the way we are? And where are we going next?

Let us first take stock.

We are genuinely remarkable members of the animal kingdom.

In The Philosophical Review for October 1974 Thomas Nagel wrote a celebrated essay: ‘What is it like to be a bat?’ In it he examined the difference between an external observer's understanding of the physical processes that occur in a bat's brain, and the bat's own mental perceptions. He argued that no amount of external observation can tell us what being a bat feels like to the bat.

Human minds do more than just recognising various bits and pieces of the universe. They look for patterns in what they recognise, and do their best to understand how the universe works. The universe, however, is very complex: in order to understand it we must also simplify it. Indeed the whole point of understanding something is that you can grasp it as a whole, and that necessitates some kind of simplification or data-compression. An explanation of the universe that was just as complex as the universe itself would merely replace one puzzle by another. In this chapter we shall argue that the brain organises its perceptions of the world into significant chunks, which we shall call ‘features’. As usual we shall take an evolutionary and contextual view of this ability, as well as asking about the internal structure of the brain. Not just ‘how does it work?’ but ‘how did it arise?’ And to get started, we shall take a look at two simpler creatures: the mantis shrimp and the octopus.

Both the octopus and the mantis shrimp are effective organisms, even if they never meet another of their own kind to learn from.

The background theory and philosophy is now out of the way, and we are ready to begin the journey from molecules to minds. It is a journey which, at every stage, involves the concept of evolution. Evolution is a general mechanism whereby systems can ‘spontaneously’ become more complex, more organised, more startling in their abilities.