Imagination, the third pillar. Dragons in clouds and buildings not yet poured: imagination runs alongside perception, not instead of it, in a proportion that shifts across a life.

When our children grow, it is amazing to see the power of imagination at a young age — and a little disappointing to watch it recede over time. From finding animals in the clouds, to playing games with symbolic toys, to the unanswerable questions, it really is a delightful thing to witness. And what amazes me is that, for some, this has been a decoupled experience. Well — I have been an engineer for forty-plus years, and even for me, I believe we need to look for a path that recognises that reality and imagination coexist in our minds. To a changing proportion over time, I would add. But if we really do live in a controlled hallucination, how is this so?

Start with that decoupled view — the one that has been taking shape in the sciences of the mind — because it is close to right, and worth stating properly. Imagining, on this account, is not a separate faculty at all — not a special image-making room set apart from perception. It is the same machinery that does your seeing, run in a different mode. Andy Clark put the perceiving half of it memorably: to perceive is not to receive the world but to predict it, the brain meeting what arrives at the senses with its best running guess. Imagination, in this telling, is that same predictive apparatus left to run when little or nothing is arriving to correct it — the model free-wheeling, offline, generating the world it expects instead of the one the senses report.

It is a clean and powerful idea, and I think it is half right. What I cannot make it fit is the felt fact that imagining does not wait for the senses to fall quiet. A child staring upward is not shutting her eyes to summon the dragon; the dragon and the cloud arrive together. When you lose an afternoon to a novel, the room does not go dark — the print keeps arriving through your eyes while a whole imagined world runs alongside it, and somehow you attend to both. Imagination, in the living of it, is not what the mind does when it stops perceiving. It runs at the same time as perceiving — a second stream, coupled to the first rather than switched in for it, and adjustable in the mix. Some people can turn it up; some can barely find the dial. Reality and imagination are not alternating. They are simultaneous.

I should be plain that this is where I leave the settled ground. That imagining and perceiving share the same machinery is now widely accepted; that the imagining runs offline is the standard reading of it. The claim that it runs alongside — coupled, concurrent, always at least faintly on — is mine to make and mine to defend, a way of seeing I am trying on rather than a result I can hand you. But it earns its keep, because it answers the question I began with.

If you follow the science one step further, you reach a startling place: even ordinary perception is not a clean window on the world. What you see is a construction — the brain’s best guess, built from expectation and corrected, where it must be, by the senses. Anil Seth calls it a controlled hallucination: a waking dream held on a short lead by reality. But if perceiving is already a controlled hallucination, then imagining cannot be a wholly separate act that begins only when perception stops. It is the same hallucination with the lead let out. Perception is the guess held tight against the world; imagination is that guess with the tether loosened on some channels while the others stay tied to what is in front of you. That is why they run together and feel like one experience. The controlled hallucination does not shut imagination out. It is precisely what leaves the door open for it.

There is a cleaner way to see how one experience can hold both. The mind is not a blank screen the world writes on; it is an accumulation — a vast synaptic matrix, the weighted structure a life lays down — and it meets each new signal not by recording it but by resonance: the incoming, already shaped by the past, finding and waking what is already there. And what is already there is not only the real. The synaptic matrix holds imagined things too — the money we have all agreed to believe in, the religion you may or may not hold, the stories and pictures and hoped-for futures — laid down alongside the taste of coffee and the colour of the sky. The match is never quite clean — and what it returns is not one settled answer but two things at once: a part that sits square with what is actually arriving, tied to the present; and a second part, coupled to it but running a little loose — slightly out of phase with the world, not quite pinned to what the senses report. That loose, out-of-phase part is not a fault in the machinery, not noise to be corrected away. It is the difference the system keeps — something extended beyond what arrived — and, gathered and accumulated over a life, that kept difference is, I suspect, where imagination comes from.

We don’t just live in a controlled hallucination. We live with a synaptic matrix that has accumulated both reality and imagination, and so all our perceptions are through an accumulated hallucination. There is no need for Kant’s transcendental idealism; this is simply how we live.

Which brings me back to the child on the grass, and to why she sees so much more in the sky than the rest of us. It is not that she owns a faculty we have lost. It is that far less of her mind is yet tied down. The developmental psychologist Alison Gopnik draws the distinction beautifully: the young mind runs like a lantern, casting light everywhere at once, where the adult mind narrows to a spotlight trained on the task. A child has not yet accumulated the mass of structure and obligation that clamps most of an adult’s attention to the sensory present. So a great deal of the child runs loose, out of phase, free to make dragons of clouds. Nothing in me switched off as I grew up. The proportion simply shifted — more of me got tied to the world and the work, and the free play receded. That is the changing balance over a life: not a light going out, but a dimmer turned, slowly, toward the real.

And the spare channels never close. They are put, instead, to fewer and more directed uses — which is the part an engineer knows in his hands. I have stood on bare ground and seen, with something close to sight, the building that was not yet there: the entrance, the fall of light through a floor not yet poured. Every structure I helped raise had to be imagined before it could be costed, argued for and built. A business is the same trick at a larger scale — a founder imagining the thing whole before a brick of it exists, and, crucially, imagining it vividly enough that others can see it too. The grandest human works are imagined ones held in common — laws, nations, the institutions we agree to treat as real — that coordinate millions and outlast everyone who carries them. This is not childhood’s imagination lost. It is the same out-of-phase stream, re-aimed and grown load-bearing. Nor is any of it uniquely human: a dog worrying a rubber toy is running a simpler version of the same thing, projecting a hunt onto a lump of rubber. What sets us apart is not the mechanism but the depth of what the mind draws on, and the symbols we have learned to run on it.

I will not pretend the picture is finished. Whether imagination truly runs coupled and concurrent, or merely switches in and out faster than we can notice, is not something a single essay settles, and the machinery beneath it is a longer argument for another place. But I would put my money on alongside, because that is how a life is actually lived — the real and the imagined braided together, moment to moment, in a proportion we lean one way in childhood and the other in middle age. The good news, if I am right, is that nothing was ever taken from you. The dragon is still there in the cloud; the dimmer only turned. To imagine well as an adult is not to recover a lost faculty but to loosen the tether again on purpose — to let a little more of the mind run out of phase with the world, and see what it makes.

Note on method. The ideas here are mine, and have been the subject of a human quest you can follow at www.integraloflife.com. As an engineer I am comfortable having them written with an LLM in support, as much as you presumably are about the software that helped design the aircraft you fly in.