Having painted a picture of a quite different ancient social structures and pre-modern cultures mostly from the outside, we will now try to discover their psychology - through interpretations that can be quite surprising and controversial. Is usually a default assumption of the modern age that while the customs and technologies of our ancestors were different, their inner lives were much the same as our own. We read the epics of Homer or the tragedies of Sophocles and imagine that the grief of Achilles or the anguish of Oedipus were felt in a way we would immediately recognize. We assume a fundamental psychological uniformity across history, a stable human nature experiencing the world through the same cognitive lens. This chapter will challenge that assumption. It proposes that while the brains of ancient peoples were biologically modern, their cognitive architecture—the functional organization of their minds—was profoundly different.
The central premise is that for much of antiquity, the mind was not a private, internal sanctum but an extended system, a dynamic loop between the organism and a carefully structured environment. This perspective moves beyond seeing the world as merely an object of thought and reframes it as a component of thought. This is a theory of "active externalism," based on the active role of the environment in driving cognitive processes. Where we see a clear boundary between the thinking self and the external world, many ancient cultures may have experienced a "coupled system," where neural, bodily, and environmental processes were so tightly integrated that they constituted a single cognitive entity. This requires a shift from a purely "brain-centric" model of cognition to one of embodied and extended cognition, where thinking happens not just in the head but through the body and in the world. This also draws on Henri Frankfort's concept of "mythopoeic thought"—the idea that Bronze Age minds operated through participatory consciousness rather than our modern subject-object distinction, experiencing gods not as separate entities but as aspects of a lived, animated cosmos where psychological and physical were undifferentiated.
This line of inquiry has provocative, if controversial, precursors. In the 1970s, the psychologist Julian Jaynes advanced the hypothesis of a "bicameral mind," arguing that until roughly 3,000 years ago, humans had a quite different psychological hardware. He posited that those ancient people did not introspect but instead experienced auditory hallucinations—the voices of gods—which were directives from one hemisphere of the brain to the other. While Jaynes's specific neurological model remains contentious, his core intuition that ancient mentality was fundamentally different provides a radical starting point. This chapter will refine that intuition, proposing a more nuanced theory grounded not in hallucination, but in a pervasive environmental integration.
To understand this different mode of being, we must first ask a simple question posed by philosophers Andy Clark and David Chalmers: "Where does the mind stop, and the rest of the world begin?".[2] The conventional answer is at the skull. The Extended Mind Thesis (EMT) argues this boundary is arbitrary. Cognition, they contend, is a process, not an organ. If a part of the world functions as a process which, were it done in the head, we would unhesitatingly call cognitive, then that part of the world is part of the cognitive process.[1]
The classic illustration of this principle is the thought experiment of Inga and Otto. Inga wants to go to the Museum of Modern Art. She consults her biological memory, recalls the address, and sets off. Otto, who has Alzheimer's disease, also wants to go to the museum. He carries a notebook everywhere he goes. When he has new information, he writes it down. When he needs old information, he looks it up. To find the museum, he consults his notebook, finds the address, and sets off. Clark and Chalmers argue that Otto's notebook plays the exact same functional role for him that biological memory plays for Inga. In both cases, the information is reliably there when needed, easily accessible, and automatically trusted. To say that Inga's memory is part of her mind but Otto's notebook is not is to betray a prejudice for what is inside the skin. Functionally, Otto's mind has been extended to include the notebook.
This principle is not limited to compensating for a neurological deficit. From the moment our ancestors first shaped a stone tool, we have been offloading cognitive tasks into the environment.[3] Cognitive archaeology allows us to see the material record not just as the products of ancient minds, but as evolving components of those minds.[4]
In the ancient world, this scaffolding went far beyond handheld tools. The most powerful cognitive technologies were the deliberately constructed environments that structured public and private life. Sacred spaces—temples, sanctuaries, and their surrounding precincts—were not merely places of worship; they were a form of cognitive architecture, external hardware for the collective mind.
These spaces served, first and foremost, to structure memory and identity. In the Greek city of Argos, for example, religious life was organized around two poles: an urban sanctuary to Apollo and a peripheral sanctuary to Hera on the city's outskirts.[5] This duality was not accidental; it physically encoded the intertwined civic and territorial identities of the Argive people. The great processions, like the Héraia, which moved between these poles, were not just parades. They were rituals that forced citizens to physically enact and thus remember the socio-political framework of their community. The very layout of the land became a distributed, public memory palace, a mnemonic device for collective history and values.
Furthermore, these spaces were not passive backdrops for action; they were active participants in guiding thought and behavior. They were often conceived as "threshold spaces," carefully delineated to separate individuals from the profane world and induce a specific mental state.[6] A boundary stone, or horos, marked more than a property line; it marked a cognitive boundary.[8] Upon entering the healing sanctuary at Epidaurus, a pilgrim was met with an inscription: "Pure must be he who enters the fragrant temple; Purity means to think nothing but holy thoughts".[7] This is a direct instruction for cognitive and emotional regulation, an external prompt to initiate an internal state. The prescribed path of a procession through a sanctuary was a guided sequence of thoughts and actions, externalizing the structure of a ritual and ensuring its correct performance, thereby offloading the mnemonic burden from the individual participant.
A sanctuary was a complete cognitive system, a network of relationships between the space, the cult statue, the myths, and the rituals, all working in concert to construct the experience of "sacredness" and facilitate what was understood as communication with the divine. This system was reliable, constantly accessible to the community, and automatically trusted—meeting all the criteria for a cognitive extension.
This deep integration of mind and environment gives us a new lens through which to understand the profound horror of exile in the ancient world. If an Alzheimer's patient's home, filled with notes and labels, is a functional part of their memory, then altering that environment is ethically akin to performing a procedure on their brain. The ancient city, with its sanctuaries, statues, and processional routes, functioned as a similar cognitive scaffold for its citizens. It held their collective memories, structured their social identity, and cued their behaviors. An ancient Greek banished from his polis was therefore not just losing his home and social standing; he was being severed from constituent parts of his own mind. This was not merely homesickness; it was a form of cognitive amputation, leaving the individual disoriented, functionally diminished, and existentially unmoored. Their "self," as a coupled system, had been violently decoupled.
The extended nature of the ancient mind also explains why hermits or autonomous individuals were rare in antiquity. A person whose cognition was distributed across sacred spaces, rituals, and divine interfaces could not withdraw from society without experiencing cognitive collapse. Without temples to orient their worldview, oracles to resolve uncertainties, and public rituals to regulate emotions, an isolated ancient individual would suffer not just social isolation but cognitive amputation.
It was only with the gradual internalization of cognitive processes—the development of introspection, conscience, and subjective reasoning—that true solitude became psychologically viable. As thinking shifted from external processes to an internal mental theater, individuals gained the capacity to "think for themselves" in a previously impossible way. The autonomous individual capable of retreating to "find oneself" presupposes an internalized cognitive architecture that simply didn't exist in ancient minds.
If the structure of the ancient mind was extended into the world, we must then ask about its content. What was the "software" that ran on this distributed hardware? A central feature of this cognitive ecology was the pervasive presence of gods, spirits, and other unseen agents. To a modern sensibility, this appears to be a matter of primitive belief. From a cognitive science perspective, however, it can be understood as a highly effective, and in some sense natural, way of interfacing with a complex and often unpredictable world.