A Definitive Catalogue of the Works and Theories of De Selby: An Inquiry into the Pataphysics of Flann O'Brien

Introduction

Within the surreal architecture of Flann O'Brien's literary universe, few figures cast as long and distorted a shadow as De Selby. He exists not merely as a character but as a central conceit, a profound and hilarious parody of scholarly ambition and the human compulsion to rationalize an irrational world. Described as an eminent "physicist, ballistician, philosopher and psychologist" , De Selby is a "savant" whose life's work is a bewildering "hodgepodge" of contradictions, a corpus of "outrageous" and "paradoxically non-scientific" theories presented with just enough "semi-scientific" justification to appear "eminently plausible at first blush". He is, in essence, the patron saint of pataphysics, the science of imaginary solutions.  

The primary lens through which we view this extraordinary figure is the unnamed narrator of The Third Policeman, a man whose life is defined by a fanatical devotion to the philosopher's work. This obsession begins in his youth at boarding school with the discovery of a tattered copy of De Selby's Golden Hours and metastasizes into the singular, driving force of his existence. It is this ambition—to compile and publish the definitive commentary on De Selby's thought—that motivates his descent into robbery and murder, the very acts that precipitate him into the bizarre, cyclical afterlife where the novel unfolds. The narrator's quest is thus inextricably linked to the intellectual labyrinth built by his idol.  

This labyrinth is made all the more complex by the existence of a meta-fictional "commentariat"—a host of fictional scholars such as Hatchjaw, Bassett, Le Fournier, and Garcia who populate the novel's extensive footnotes. Their endless, bitter feuds over the interpretation of De Selby's esoteric pronouncements serve as a perfect satire of academic pedantry, where the scholarly apparatus becomes as absurd as the subject it purports to illuminate. This is encapsulated perfectly by one of De Selby's fictional biographers, who is quoted as saying, "The beauty of reading a page of de Selby is that it leads one inescapably to the happy conviction that one is not, of all nincompoops, the greatest".  

The character of De Selby undergoes a significant evolution across O'Brien's work. In The Third Policeman, he is an unseen historical figure, a ghostly intellectual presence whose theories provide a skewed philosophical compass for the narrator's journey through hell. In the later novel, The Dalkey Archive—for which O'Brien "cannibalized" parts of the then-unpublished manuscript of The Third Policeman —De Selby is resurrected as a living, breathing character. Here, he is no longer just a harmless crank but a dangerous antagonist bent on world destruction, a mad scientist who must be stopped.  

This report aims to provide a definitive and exhaustive catalogue of the experiments, inventions, and theories attributed to De Selby across both novels. It will collate and analyze the disparate elements of his "work," distinguishing between his own propositions and the related pataphysical phenomena that permeate his universe. By examining each concept in detail, this report will illuminate not only the strange genius of De Selby but also the profound satirical project of his creator, Flann O'Brien.

Table 1: A Synoptic Index of De Selby's Works and Associated Phenomena

Theory / Invention	Primary Source(s)	Brief Description
Static Human Existence	The Third Policeman	The belief that life is a series of still moments, not a continuous flow.
Journeys as Hallucinations	The Third Policeman	The corollary that travel is an illusion, demonstrated via postcards.
"Black Air" Theory of Night	The Third Policeman	Posits that night is a physical accumulation of dark, insanitary matter.
Mirror-Time Theory	The Third Policeman	The use of mirrors to view one's own past due to the finite speed of light.
Sausage-Shaped Earth	The Third Policeman	A theory of geodesy that redefines travel and existence, rendering death "unnecessary".
Onomatopoeic Theory of Names	The Third Policeman	The idea that names are decodable prehistoric grunts describing appearance.
Houses as Degenerative	The Third Policeman	The belief that conventional housing is the root of human degradation.
Architectural Designs	The Third Policeman	Practical solutions to housing, including "walls without roofs and roofs without walls".
Water Dilution Experiment	The Third Policeman	An attempt to fundamentally weaken or dilute the substance of water.
D.M.P. Substance	The Dalkey Archive	A chemical compound that removes oxygen, disrupts time, and ages whiskey.
World-Destruction Plan	The Dalkey Archive	The ultimate goal to use D.M.P. to annihilate the atmosphere.
Atomic/Mollycule Theory	The Third Policeman, The Dalkey Archive	A police theory of atomic exchange between frequent riders and their bicycles.
Omnium Energy	The Third Policeman	The fundamental energy of the universe, harnessed by the police.
Sound-to-Light Machine	The Third Policeman	A police contraption that converts sound into light via omnium.

Part I: The De Selbyan Cosmogony: Theories of Time, Space, and Existence

This section is dedicated to De Selby's grand, abstract philosophical propositions that seek to redefine the fundamental nature of reality. These theories form the bedrock of his intellectual system and provide the philosophical underpinnings for the surreal events of The Third Policeman.

1.1 The Static Nature of Being and the Hallucination of Travel

At the heart of De Selby's philosophy lies a radical reconceptualization of existence itself. His foundational thesis is that human life is not a continuous, flowing river, as commonly perceived, but rather "a succession of static experiences each infinitely brief". This atomistic view of existence directly challenges the intuitive understanding of time and motion, positing that what we experience as progression is merely an illusion created by a sequence of still points.  

From this core premise, De Selby logically derives his most famous and oft-quoted aphorism: "a journey is a hallucination". If life is composed of discrete, static moments, then a "traveller" is, by definition, never truly in motion. Instead, they are simply experiencing a rapid succession of infinitesimal pauses, much like the individual frames of a cinematograph film that create the illusion of movement. The photograph is cited as the ultimate proof of this thesis, capturing a single, static instant and revealing the "truth" behind the illusion of continuous travel.  

De Selby did not confine this theory to the realm of abstract thought. He claimed to have provided a rigorous experimental proof by undertaking a "journey" from Bath to Folkestone without ever leaving his study. This peculiar experiment involved a meticulous arrangement of props: a collection of picture postcards depicting the supposed route, an array of barometric instruments to simulate changes in altitude and weather, clocks to mark the passage of "time," and a specially designed apparatus to regulate the gaslight, mimicking the changing quality of sunlight at various points in the "day". By engaging with this curated sequence of static data points, De Selby believed he had successfully replicated the experience of the journey, thereby proving it to be a construct of perception rather than a physical translocation.  

The significance of this theory extends far beyond its surface absurdity. De Selby's experiment is a masterful parody of the scientific method and empirical inquiry. He gathers "data" (postcards, instrumental readings) and establishes a controlled environment to test a hypothesis, mimicking the procedures of a legitimate scientist. However, the entire enterprise is a solipsistic, closed loop. He is not testing a hypothesis against the external world; he is using a carefully constructed hallucination to prove that his experience is a hallucination. This intellectual folly provides a crucial key to understanding the narrative structure of The Third Policeman. The narrator, having been murdered, is trapped in a hell that is a cyclical, repetitive, and static experience. His "journey" through the bizarre parish is, in the most literal sense, a hallucination built from the components of his own life, obsessions, and guilt. Progress is impossible because he is doomed to repeat the same loop eternally. De Selby's theory, therefore, is not merely a quirky philosophical aside; it is a foundational law of the novel's universe, a meta-commentary on the nature of the narrative itself, which traps both the character and the reader in a seemingly endless succession of static, terrifying moments.  

1.2 The Materiality of Night: Accretions of "Black Air"

De Selby's revolutionary zeal was not limited to time and space; he also launched a full-scale assault on conventional astronomy. He flatly rejected the accepted explanation for the phenomenon of night, dismissing the rotation of the Earth as a simplistic fiction. In its place, he proposed a theory of startling materiality: night, he argued, is caused by a gradual "accumulation of 'black air'". This substance, also described as "clouds of black pollution" , is not a mere absence of light but a tangible, physical contaminant that stains the atmosphere. The source of this "black air" is attributed to mysterious and unspecified volcanic activities, which release fine particulate matter into the sky.  

The consequences of this theory for humanity are dire. De Selby describes the condition of night as "insanitary". The "black air" is not a benign presence but a pervasive pollutant that directly affects human physiology. In his view, the state of sleep is not a natural biological process of rest and recuperation. Instead, it is a pathological condition: a series of "fainting-fits brought on by semi-asphyxiation" as individuals are forced to inhale the toxic, stained atmosphere. This recasts the fundamental rhythm of life, the cycle of day and night, as a "secondary hallucination" that takes place within the "supreme hallucination" of human existence.  

This theory operates as a classic pataphysical inversion, taking a poetic or metaphorical concept—the "darkness" of night—and treating it as a literal, physical substance with measurable properties and effects. This has a profound impact on the atmosphere of the novel. The world of The Third Policeman is not just metaphysically strange; it is physically oppressive and unhealthy. The very air is suspect, a source of contamination. This is reinforced by the narrator's own experience upon entering the otherworld, which he describes as a sudden, unnatural change in the air's density, as if it had "become twice as rare or twice as dense" in an instant.  

Furthermore, the theory taps into pre-scientific, almost Gothic, notions of miasma—the idea that disease and madness are carried on unhealthy vapors and foul air. O'Brien masterfully weaponizes these archaic scientific beliefs for literary effect. The "black air" theory, therefore, does more than provide another example of De Selby's eccentricity. It fundamentally alters the ontology of the novel's world, transforming it into a physically and spiritually suffocating space. It provides a "scientific" rationale for the story's oppressive, dream-like quality, directly linking De Selby's intellectual folly to the sensory experience of the narrator's damnation.  

1.3 The Mirror as Chronoscope: Gazing into the Past

Among De Selby's most imaginative propositions was his belief that "mirrors held the secret to eternity". This theory, like many of his others, is founded upon a hyper-literal and doggedly pursued interpretation of a simple scientific principle: the finite speed of light. De Selby reasoned that because light takes a non-zero, albeit infinitesimal, amount of time to travel from an observer's face to the surface of a mirror and then back to the observer's eye, the reflection one sees is not a true, instantaneous reproduction. Instead, "what he sees is not a true reproduction of himself but a picture of himself when he was a younger man".  

While this time lag is imperceptible in a single reflection, De Selby was not deterred. He extrapolated this principle to its most extreme and logical conclusion. He claimed to have designed and constructed a complex experimental apparatus consisting of "a huge array of parallel mirrors". The purpose of this arrangement was to capture and multiply the minuscule time delay through a series of successive reflections. By gazing into the final mirror in this sequence, De Selby alleged that he had succeeded in looking back into his own past, claiming to have glimpsed his own face as it appeared when he was a boy of twelve.  

This experiment serves as a powerful and poignant metaphor for memory, nostalgia, and the inescapable nature of the past. The universal human desire to see one's younger self, to recapture a moment of lost time, is here given a physical, mechanical form. De Selby's apparatus is a brilliant parody of technological solutionism—the distinctly modern belief that any problem, no matter how existential, can be solved with a sufficiently clever machine. He attempts to engineer a solution to the melancholy of time's passage.

This connects directly to the central tragedy of the narrator's story. He is trapped in a purgatorial loop, forced to endlessly relive the consequences of his past actions but without the awareness or understanding to escape. He is, in a sense, living permanently in his own past, but he cannot "see" it clearly or comprehend its meaning. Like De Selby, who can only claim a fleeting "glimpse" of his boyhood self , the narrator is denied true access to the past that defines him. The mirror theory thus becomes a potent symbol for the novel's thematic core. It suggests that the past is always present, a ghostly image that haunts us, but it can never be truly re-entered, altered, or understood. De Selby's "solution" to the problem of time, like all his solutions, only serves to deepen the existential dilemma it purports to solve.  

1.4 Aberrant Geodesy: The "Sausage-Shaped" Earth

De Selby's intellectual ambition culminated in a grand unified theory that sought to redefine not only physics but also geography and theology. He began by rejecting the conventional spherical model of the Earth. His reasoning was, as ever, based on a perverse and unassailable logic: since any journey undertaken on the planet's surface, regardless of direction, will eventually return the traveller to their starting point, one cannot definitively prove that the Earth is a sphere. Any number of other shapes could produce the same result. The shape he proposed was that of a "sausage".  

This was more than a simple geometric substitution. De Selby theorized that humanity was constrained to travel in a single, limited dimension around the "skin" of this sausage. However, he believed it was theoretically possible to travel in a different direction—along the "barrel" of the sausage, from one end to the other. If such a journey could be accomplished, he argued, "new and unimaginable dimensions will supersede the present order". This dimensional shift would have a profound consequence: it would eliminate what he termed the "manifold 'unnecessaries' of 'one-dimensional' existence". In a list provided by one of his commentators, these "unnecessaries" are revealed to be the most fundamental and inescapable conditions of human life: "bereavement, old age, love, sin, death".  

This theory represents the most explicitly theological of De Selby's propositions in The Third Policeman. It is a quasi-scientific schema for achieving salvation, proposing a physical, mechanical means of escaping human suffering and mortality. The language used—"unnecessaries," "new and unimaginable dimensions"—is a deliberate parody of the promises made by mystical, Gnostic, or religious systems that offer transcendence from the pains of the material world.

The irony of this theory in the context of the novel's plot is devastating. The narrator commits a brutal murder, the ultimate act of inflicting mortality, in order to acquire the funds to publish his definitive work on De Selby—a philosopher who believes that death itself is merely an "unnecessary" feature of a poorly understood geography. The narrator kills to better understand a philosophy that claims death is an illusion. This theory is the philosophical carrot that leads the narrator down the path to his own damnation, promising an escape from the very condition he is about to permanently enter. The sausage-earth theory is De Selby's ultimate intellectual hubris: the belief that even the problem of death can be solved with a better map.

Part II: Practical Pataphysics: De Selby's Experiments and Inventions

This section transitions from De Selby's abstract, cosmological theories to his more applied works. Here, we catalogue the tangible experiments, physical apparatuses, and practical designs that emerged from his unique philosophical framework. These inventions demonstrate the often-calamitous results of applying his pataphysical principles to the real world.

2.1 Architectural Aberrations: The War on Houses

De Selby's critical gaze fell not only upon the heavens but also upon the humble human dwelling. He harbored a deep-seated philosophical animosity towards conventional architecture, positing that houses are "the root cause of degradation of the human race". He regarded a typical street of houses as nothing more than "a row of necessary evils" , artificial constructs that alienate humanity from its natural state. This belief was not an isolated quirk but stemmed from his broader critique of the artificiality of civilized life.  

In response to this perceived crisis, De Selby moved from theory to practice, designing what he termed "preferable 'habitats'". These designs were not modest improvements but radical deconstructions of the very idea of a house. Taking the ideal of "openness" to its most literal and illogical conclusion, his architectural solutions came in two principal forms: structures consisting of "walls without roofs and roofs without walls".  

These architectural concepts function as a multi-layered satire. On one level, they can be read as a parody of the more extreme and dogmatic tenets of architectural modernism, which often emphasized the breaking down of traditional forms and the blurring of the boundary between indoor and outdoor space. De Selby's designs push this ideal to the point of utter absurdity. Simultaneously, they mock a certain brand of philosophical primitivism—the romantic notion that civilization and its structures are inherently corrupting and that a return to a more "natural" state is desirable.

The sheer impracticality of the designs exposes the folly of pursuing a philosophical ideal divorced from the realities of human need. A roof without walls offers no shelter from the wind, while walls without a roof provide no protection from the rain. This demonstrates De Selby's characteristic thought process in miniature: first, identify a grand "problem" (the degenerative effect of houses); second, propose a radical "solution" based on a rigid, literal interpretation of an abstract ideal (openness); and third, completely ignore the practical, nonsensical consequences of this solution. It is a perfect example of his intellectual pathology, where logic is pursued so relentlessly that it circles back into pure madness.

2.2 An Inquiry into Fundamental Properties: The Dilution of Water

Among the most esoteric and tantalizingly vague of De Selby's scientific endeavors is an experiment, mentioned in a passing footnote, to "dilute water". The lack of detail surrounding this attempt only adds to its mystique and its power as a piece of intellectual comedy. The philosophical basis for such an experiment appears to be a perverse modification of the pre-Socratic philosopher Thales's famous proposition that water is the  

arche, the fundamental substance from which all else is derived. It seems De Selby, accepting this premise, sought to investigate whether this primary, elemental substance could itself be weakened, attenuated, or fundamentally diluted.  

The very concept of "diluting water" pushes against the boundaries of both logic and language. Water is the universal solvent; it is the medium one uses to dilute other substances. The phrase itself is a semantic and logical paradox, an idea that is simple to state but impossible to conceptualize in any meaningful way. It is a proposition that attacks the foundational logic embedded within our language, a hallmark of O'Brien's humor, which often derives its power from exploring the absurd consequences of taking language too literally.  

The importance of the water dilution experiment lies not in any imagined methodology or result, but in its sublime conceptual absurdity. It is a perfect demonstration of De Selby's intellectual hubris and his willingness to challenge not just the known laws of physics, but the very axioms of thought upon which human understanding is built. It represents a mind so untethered from common sense that it sees no contradiction in attempting to make the universal solvent a solute in itself. It is a thought experiment that reveals the comic potential of philosophical inquiry when it is completely detached from reality.

2.3 The D.M.P. Compound: A Substance to Unravel Reality

In The Dalkey Archive, De Selby's work takes a practical and far more dangerous turn with the invention of a mysterious chemical substance known as D.M.P. This compound is the ultimate expression of his genius, a single substance capable of manipulating physics, metaphysics, and even commerce. The name itself is a piece of typical O'Brien bathos: the acronym stands for the Dublin Metropolitan Police , a bizarrely parochial and mundane name for a compound with the power to alter the fabric of reality.  

The substance possesses a remarkable tripartite function. First, its primary physical effect is de-oxygenation. When released in an airtight enclosure, D.M.P. has the ability to extract every particle of oxygen, creating a perfectly anaerobic environment.  

Second, this physical process has a profound metaphysical side effect: time disruption. The removal of oxygen somehow "disrupts the sequentiality of time" and forces human perception to align with what De Selby believes is the true nature of time: "simultaneity". Within this timeless, de-oxygenated state, it becomes possible to converse with individuals who exist outside the normal flow of history. De Selby uses this property to hold conversations with figures from the Christian past, most notably Saint Augustine, whom he summons in a secret underwater cave.  

Third, as an incidental and comically practical benefit, the process has an application in accelerated maturation. The same temporal disruption can be used to age spirits, making it possible to produce "fine mature whiskey in a week" that would normally require decades of aging.  

D.M.P. perfectly embodies O'Brien's comic style by constantly juxtaposing the mundane with the cosmic, the banal with the apocalyptic. A substance that can unravel time, facilitate conversations with saints, and potentially end all life on Earth can also be used to make cheap, fast whiskey. The sublime ambition of the philosopher is perpetually undercut by a very Irish, very pragmatic concern. The substance acts as a perfect "phlebotinum"—a versatile, all-purpose plot device that can do whatever the story requires of it. Its "scientific" basis is irrelevant; its function is to enable the novel's bizarre encounters and to serve as the engine for its satirical plot. D.M.P. is the ultimate product of De Selby's mind: a tool of immense and terrifying power that reflects the chaotic mixture of high-minded philosophy, crackpot science, and base desires that defines its creator.  

2.4 The Eschatological Project: The Annihilation of the Atmosphere

The De Selby of The Dalkey Archive is no longer the detached, historical theorist of The Third Policeman. He is an active agent with a terrifyingly practical goal. His ultimate invention is not a substance, but a plan: a "wicked plan" to deploy his D.M.P. compound on a global scale. His eschatological project is to "destroy the world in the name of God" by using D.M.P. to remove all the oxygen from the atmosphere, thereby annihilating all aerobic life on the planet.  

This apocalyptic ambition stems from a messianic delusion. Through his D.M.P.-induced conversations with historical figures and his own philosophical reflections on the "horrid nature of the material world," De Selby has come to believe that he is a new Messiah, tasked by God with the sacred duty of bringing about the end of a corrupt and fallen creation. His project is a satire of both religious and scientific apocalypticism. He employs a scientific tool (the D.M.P. compound) to achieve a fanatical theological end (a twisted version of God's judgment).  

This plot point can be read as a domestic-scale parody of the Cold War anxieties that permeated the mid-20th century. O'Brien replaces the terrifying but abstract threat of the atomic bomb with a canister of bizarre chemicals wielded by a crank philosopher in a Dublin suburb. This act of domesticating the apocalypse makes it at once more tangible and more absurd. The plan provides the central narrative thrust for The Dalkey Archive, transforming the intellectual quest of the first novel into a pulp-style adventure. The unlikely hero, Mick Shaughnessy, a "lowly civil servant," must thwart the mad scientist and save the world. This final project represents the ultimate and logical trajectory of De Selby's thought. His lifelong intellectual detachment and his profound contempt for the messiness of the physical world culminate, quite reasonably from his perspective, in a desire to annihilate it. It is the final, insane, and perfectly consistent step for a philosopher who has successfully reasoned himself out of existence.  

Part III: The Parish Pandemonium: De Selby-esque Phenomena

This final section analyzes concepts from The Third Policeman that, while not explicitly attributed to De Selby, are so thoroughly infused with his brand of pataphysical logic that they form an essential part of his intellectual landscape. These phenomena, originating with the eccentric policemen of the parish, demonstrate that De Selby's madness is not an aberration but the very law of the land in the narrator's hell.

3.1 The Atomic Theory of Bicycles

It is crucial to establish that the famous "Atomic Theory" of bicycles is not an invention of De Selby. It is a piece of local, folk physics explained to the bewildered narrator by Sergeant Pluck. The theory is later recycled in  

The Dalkey Archive, where it is presented as Sergeant Fottrell's "Mollycule Theory". Despite its separate origin, it is the perfect practical counterpart to De Selby's abstract speculations.  

The theory posits that through prolonged and violent contact—the "thump and deathly steel" of riding iron bicycles over the "rocky roadsteads" of the parish—a constant interchange of atoms occurs between a rider and his bicycle. As Sergeant Pluck explains, "Everything is composed of small particles of itself...spinning away and darting hither and thither". This constant kinetic bombardment causes the atoms of man and machine to become intermingled.  

The consequences of this atomic exchange are profound and transformative, leading to a bizarre symbiosis. People who spend most of their lives on a bicycle become progressively more bicycle-like. Their personalities and physical habits change, and they spend an increasing amount of their time "leaning with one elbow on walls or standing propped by one foot at curbstones". Sergeant Pluck is so concerned by this phenomenon that he keeps his own beloved bicycle locked in the barracks' lone jail cell to prevent her from becoming too human. Conversely, the bicycles themselves become more human, partaking of their riders' personalities and developing a cunning and independent will. They are known to hide themselves in convenient places, tempting unsuspecting people to ride them. This process is quantifiable; the Sergeant keeps a ledger in which he records the bicycle-percentage of each man in the parish. The theory has legal ramifications as well: in the extreme case of a murderer named MacDadd, who was judged to be more than half bicycle, it was his bicycle that was ultimately hanged for the crime.  

The Atomic Theory serves as a perfect, street-level parallel to De Selby's academic work. It takes a modern scientific concept—atomic theory—and applies it with the same relentless, absurd literalism that De Selby applies to the speed of light or the nature of time. The key difference lies in class and context. De Selby's theories are the esoteric products of a solitary, wealthy "savant," debated in obscure scholarly texts. The Atomic Theory is a form of folk-pataphysics, a local phenomenon observed, documented, and policed by the common man in the form of the parish sergeant. This has a powerful effect on the narrative, demonstrating to the narrator that he has not simply stumbled into the sphere of influence of one mad philosopher. Rather, he has entered a universe that operates on these principles at every level. The fundamental laws of physics in this hell are De Selbyan. The Atomic Theory of Bicycles is perhaps the most famous and enduring concept from the novel precisely because it grounds the book's abstract philosophical comedy in a tangible, hilarious, and deeply weird image. It proves that De Selby is not an outlier; he is simply the one who bothered to write it all down.

3.2 Omnium and Its Applications

Another set of phenomena unique to the police barracks revolves around a mysterious energy source known as "omnium." This is defined as "the fundamental energy of the universe" , a concept that, like the Atomic Theory, originates not with De Selby but with the policemen themselves. The policemen, particularly the inventive Policeman MacCruiskeen, are not just enforcers of the law but are tinkerers and inventors in their own right. They have managed to harness omnium for their own peculiar purposes.  

The most notable of their inventions is a "contraption that collects sound and converts it to light based on a theory regarding omnium". This is not their only creation; they have also built machines that can perform the reverse operation, converting light back into sound, or transforming light into heat. These miraculous feats of engineering—along with MacCruiskeen's other hobbies, such as crafting a series of impossibly small, perfectly detailed wooden chests, each nestled inside the other down to a microscopic scale—are presented to the narrator with a mixture of pride and nonchalance.  

The existence of these inventions serves to reinforce one of the novel's central and most despairing themes: the ultimate futility of knowledge and creation in a meaningless universe. The policemen's inventions are, by any measure, miraculous. They have tapped into the fundamental energy of creation and built machines that defy the known laws of physics. Yet, these wonders are entirely useless. They are not used to improve life, to solve problems, or to enlighten humanity. They are created out of boredom, as a way to pass the time in the strange eternity of the police barracks. They are marvels without purpose, wonders without application.  

This provides a direct parallel to De Selby's own life's work. His theories are intellectually dazzling (at least to the narrator), and his experiments are ambitious, but they are ultimately sterile exercises that lead nowhere productive. His journey-by-postcard is a solipsistic game, and his mirror-chronoscope offers only a fleeting and useless glimpse of the past. The concept of omnium and the machines it powers demonstrate that even the ability to manipulate the very fabric of the universe is, in the hell of the parish, just another hobby. It is a way to pass the endless, cyclical time, a perfect reflection of the narrator's own futile, lifelong project of studying the magnificent but ultimately empty work of De Selby.

Conclusion

The collected works of De Selby, scattered across the narrative and footnotes of Flann O'Brien's novels, amount to one of the most sustained and brilliant creations in comic literature. This catalogue of his experiments, inventions, and theories reveals a complete, if completely insane, philosophical system. De Selby is not merely a collection of jokes; he is a masterful and coherent parody of scholarly and scientific hubris, a figure through whom O'Brien launches a profound critique of the systems of knowledge by which humanity attempts to make sense of an irrational world.

The analysis of his work reveals several key conclusions. First, De Selby's theories, from the static nature of existence to the material substance of night, form a consistent intellectual framework that meticulously parodies the methods and language of real science and philosophy. By taking a simple premise—the finite speed of light, the existence of atoms, the concept of a fundamental element—and pursuing it with a relentless and literal-minded logic, De Selby arrives at conclusions that are both unassailably reasoned and utterly absurd. This is the engine of O'Brien's satire: an attack on a form of rationalism so detached from common sense that it becomes a species of madness.

Second, the evolution of De Selby from the unseen, historical theorist of The Third Policeman to the living, world-threatening antagonist of The Dalkey Archive marks a significant development in O'Brien's own literary project. It reflects a shift from a purely philosophical and internalized narrative of damnation to a more externalized, action-driven satire. The character's trajectory from intellectual folly to active malevolence suggests a grim endpoint for a mind that holds the material world in such contempt: the logical conclusion is to seek its annihilation.

Finally, the presence of De Selby-esque phenomena within the police barracks—most notably the Atomic Theory of Bicycles and the harnessing of omnium—is perhaps the most crucial element for understanding the novel's universe. It proves that the narrator has not simply fallen into the world of one madman's books. Instead, he has fallen into a world where that madness is the governing law of physics. The folk-pataphysics of the policemen validates the academic pataphysics of De Selby, confirming that his intellectual system is not an aberration but an accurate description of the reality of the narrator's purgatorial existence.

Ultimately, the complete catalogue of De Selby's inventions and theories is a catalogue of the magnificent, terrifying, and hilarious follies of the human mind. Through this fictional savant, Flann O'Brien does more than mock pedants and philosophers; he explores the very nature of reality, illusion, and the stories we tell ourselves to keep the encroaching absurdity at bay. De Selby's work is a testament to the idea that the search for knowledge, when untethered from wisdom, can become its own special kind of hell.