Diaspora (1997) by Greg Egan

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Permutation City (1994) Book Review

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Review

Diaspora is set in the far future, in a world where bioengineering has led to the speciation of humanity and virtual reality has given rise to communities of simulated consciousness known as polises. Greg Egan envisions a spacefaring civilisation composed entirely of digital lifeforms, extending the possibilities of simulated existence explored in his earlier novel Permutation City (1994). In doing so, Diaspora offers a profound investigation into the nature of consciousness, identity and what it means to be human.

The novel opens with the birth of Yatima, a virtual citizen who, unlike many inhabitants of the polises, has no human ancestry. Yatima develops within the Konishi polis, a community devoted to abstract mathematics and philosophy, undergoing an accelerated education that takes just three days of real time, with subjective time passing approximately 800 times faster. When a catastrophic gamma-ray burst devastates Earth, threatening biological life with extinction, Yatima and fellow citizen Inoshiro attempt to rescue surviving humans by persuading them to upload their consciousness into the polises, whose underground infrastructure has survived the disaster. To interact with the physical world, they inhabit anthropoid robotic bodies known as gleisners.

Meanwhile, several polises are preparing an ambitious migration into space, known as the Diaspora. Much of the novel follows the Carter-Zimmerman polis, a community dedicated to physics and understanding the cosmos, as its citizens venture ever deeper into space. The narrative moves between different copies of the same individuals, whose diverging experiences and discoveries gradually reshape their understanding of reality.

Egan’s background in mathematics lends extraordinary precision to his hard-science worldbuilding while informing his economical, confident prose. His account of Yatima’s birth is particularly remarkable. Drawing on neurobiology and computational models of learning, Egan describes the emergence of consciousness through thousands of rapidly unfolding developmental iterations. Yatima gradually acquires self-awareness through experimentation and adaptation, a process rendered with surprising poetic delicacy. Within three days of its creation, the young consciousness is already studying advanced mathematics.

Yatima encounters considerable resistance when attempting to persuade biological humans to join the polises. Yet Egan refuses to reduce the conflict to a simple opposition between human and machine. Bioengineering has already undermined any stable definition of humanity. Biological humans, known as fleshers, have diversified into numerous genetically distinct populations, their physical embodiment often the only meaningful characteristic they retain in common.

Generations of genetic modification have produced enhancements ranging from disease resistance and amplified intelligence to radical life extension and adaptation to unfamiliar environments. Some groups have deliberately abandoned higher cognitive functions and speech in pursuit of a more primal existence, recalling the Devaki of David Zindell’s A Requiem for Homo Sapiens (1993–1998). Others, known as bridgers, have modified their minds to facilitate communication and understanding between increasingly divergent branches of humanity.

This fragmentation recalls a central preoccupation of postmodern space opera, where technological advancement drives the emergence of competing posthuman species and ideologies. Bruce Sterling’s Schismatrix (1985) provides an influential early example, exploring the division of humanity between genetically engineered Shapers and cybernetically enhanced Mechanists. In Diaspora, however, speciation has advanced so far that the idea of a single human identity has become almost meaningless.

Where much science fiction treats machine intelligence as a precursor to technological singularity, social collapse or existential catastrophe, as in the works of David Zindell, Dan Simmons, Vernor Vinge, Michael Swanwick, Alastair Reynolds and Charles Stross, Egan offers a strikingly different vision. His polises are largely devoted to the pursuit of knowledge for its own sake, rather than domination, expansion or material accumulation, an idea also explored by Rudy Rucker in Realware (2000).

By removing the biological body from the equation, Egan imagines forms of consciousness liberated from many of the pressures that have historically shaped human civilisation, particularly reproduction, physical survival and the fear of biological death. Although their underlying cognitive structures retain connections to human neurobiology, the citizens of the polises are free to pursue intellectual and existential goals on radically different timescales.

For simulated beings, time itself becomes a malleable resource. The polises can undertake projects lasting centuries or millennia, adjusting the speed of subjective experience to accommodate extraordinary intellectual ambitions. Their inhabitants need not experience distance, duration or mortality in recognisably human terms.

Egan transforms these possibilities into the novel’s governing narrative structure. As the Diaspora ventures across immense distances, and eventually confronts realities beyond the familiar universe, different instances of the Carter-Zimmerman citizens pursue separate investigations, exchanging discoveries across vast stretches of space and time. What might otherwise become an unwieldy sequence of scientific explorations instead forms a coherent investigation into the nature of reality and the possibilities of conscious existence.

In Diaspora, technological transcendence is neither an inevitable catastrophe nor simply an escape from the limitations of the human body. It opens the possibility of forms of life whose ambitions, perceptions and intellectual horizons extend far beyond those of biological humanity. Egan’s achievement lies in making these radically unfamiliar modes of existence intellectually convincing while preserving the curiosity and sense of wonder that drive the novel forward.