This page compares the CTMU to other theories with similar goals or perspectives.
Before the CTMU
Langan observes that Spinoza's attempt to devise a theory of reality combining logical theology with a rationalistic approach to science is shared by the CTMU. He draws parallels between elements of Spinozan metaphysics—its logical outlook, its dual-aspect monism, and its cosmic self-containment—and his own Three Cs / Three Ms, characterizing Spinoza's system as a sort of "entry-level CTMU prototype".
At the same time, Langan notes certain crucial points of departure between Spinoza's work and his own. Whereas Spinoza viewed human intentionality as deterministic, the CTMU extends freedom to human agents "by virtue of a new conception of spacetime structure". While the CTMU is also a dual-aspect monism, it asserts that the basic substance of reality is infocognition. And whereas Spinoza's work only adumbrates the metalogical axioms of the CTMU, Langan explicitly formulates and applies them to construct a whole new proof of God's existence.
The 18th-century German philosopher Immanuel Kant held that the human mind has built-in "categories" of perception and cognition. These categories, or fundamental concepts of the understanding, function as constraints on phenomenal reality, the world of our experience. Thus, our experience of reality is constrained by the structure of our minds. Langan shares this notion, characterizing our mental structure in terms of a "syntax", or set of structural and functional rules. In the CTMU, the set of rules by which our minds operate is called the Human Cognitive Syntax or HCS.
Kant went on to posit a noumenal reality of "things in themselves", independent of our experience. Under this view, what we experience of reality are only phenomena (appearances), whereas reality in itself (noumenal reality) is unknowable. This picture led Kant to an agnosticism about the claims of traditional metaphysics. By contrast, Langan rejects the notion of noumena, arguing that the definition amounts to "inconceivable concept" and is thus an oxymoron. This leaves phenomenal reality, the only reality we can know, as the only reality there is. Consequently, the structure of our minds is a constraint on reality itself. This means that mind and reality are linked in mutual dependence, and raises the possibility that from the structure of our minds, we can draw conclusions about the structure of reality. The CTMU is essentially a theory of this linkage between mind and reality.
The Urantia Book
Terence McKenna had long placed a lot of importance on the phrase "the world is made of language". Obviously, there is much synergy in this statement and concepts in the CTMU. McKenna has placed interesting correlations with the intersection of mankind's evolution and hallucinogenic, psychedelic substances, which may have had a role in the development of language.
Also, one of McKenna's own theories, which he called "novelty theory" and "the timewave", put forth an iterative style of fractal time measurement, which helped track the significant events of universal developmental processes in terms of change and progress. Though the theory has long been dismissed and gone unconsidered, it had an interesting take toward prediction of temporal events. He called nature a "novelty conserving engine", which, as he explained, always built upon the successes of the past and reiterated these processes, folded them in on themselves, and the universe has long been undertaking this task since the beginning. Aside from entropic forces, the way in which complexity is accelerated upon the successful integration of previous complexity, building upon itself, indicates a means by which trends might be teased out of the threads of historical causation and reveal the presence of an "attractor". Instead of historical process being a "push from behind", McKenna envisioned it as being "pulled from the future". (Right here one can see a similarity of intent with Langan's distribution of causation and telesis.) However, McKenna used the I Ching to be the mathematical "fuel" with which the engine operated. Is there a meaningful, mathematical process which could legitimately deduce trends in time and perhaps even their conclusions and evolutions?
After the CTMU
Mathematical Universe Hypothesis (Max Tegmark)
Tegmark holds that mathematical and physical existence are equivalent, and that all structures that exist mathematically also exist physically, forming a "Level IV multiverse". Our universe is one of the structures in the multiverse, and observers like us are "self-aware substructures".
In the CTMU, reality is also viewed as a mathematical structure. In fact, the CTMU constitutes an answer to the very question that Tegmark aims to solve: what is the mathematical structure to which the universe is isomorphic? That structure is SCSPL (Self-Configuring Self-Processing Language). However, the CTMU avoids blanket physical reification of the "Level IV multiverse" in favor of a teleological approach.
Langan writes that "Tegmark's attempt at a TOE leaves unanswered a number of deep philosophical questions." Among them: What good does it do to explain the universe in terms of a multiverse unless one can explain where the multiverse came from? If physics comes from mathematics, where does mathematics come from? What is the relationship between subjective and objective reality?
Langan concludes that on the basis of what Tegmark's theory omits, he is merely "skirting the boundary" of a real TOE. In contrast, the CTMU deals directly with the deeper philosophical issues, outstanding paradoxes, and fundamental interrelationship of mathematics and physics.
The CTMU was created in the mid-1980s and published in 1989/1990; it therefore predates process physics, which grew from a 1996 paper by Reginald Cahill and Christopher Klinger (pdf). There are similarities: both theories view time as an iterative process rather than as an ordinary linear dimension; both seek to model reality without assuming pre-existing objects or laws; both employ concepts of self-organization; both distribute over reality a form of self-awareness.
A major difference, though, is that whereas the CTMU reduces reality to infocognition and ultimately to telesis, process physics is not a reductionistic theory at all. Cahill writes, regarding the basic iterator by which his bootstrap model evolves:
It is important to note that process physics is a non-reductionist modelling of reality; the basic iterator (2) is premised on the general assumption that reality is sufficiently complex that self-referencing occurs, and that this has limitations. ["Process Physics: From Information Theory to Quantum Space and Matter", page 17]
So the basic iterator—which New Scientist in a 2000 article called "largely the child of educated guesswork"—relies on what Cahill admits is a foundational assumption. At this level, process physics leaves reality unexplained, simply taking for granted that it possesses the complexity needed for self-reference. If it turns out that such complexity does not come for free, but rather imposes constraints on the structure of reality, then those constraints will govern process physics.
The CTMU says that self-referential complexity does impose a constraint: that reality take the form of an algebraic structure Langan calls a Self-Configuring Self-Processing Language (SCSPL). Unlike process physics, the CTMU contains, according to Langan, no assumptions:
Because the CTMU is based on logic, i.e. logical tautologies, plus a small set of metalogical tautologies, it has been described as a "supertautology". No assumptions are necessary, only laws of mathematics.
So if Cahill's and Langan's models are to be reconciled, process physics must be embedded in, and must conform to, the deeper reality of SCSPL. The CTMU is therefore the more fundamental of the two theories.
My Big TOE (Thomas Campbell)
SOURCES: More Than Allegory, p.193-194, "The circularity of consensus reality"
Kastrup's story in Part III depicts "the Other" describing reality/realities as circular, self-sustaining conceptual loops of belief systems. He alludes to the self-referential qualities of these constructs, which certainly smacks of the CTMU's use of tautology. However, when the Other says, "If you were to righteously proclaim that classical logic were self-evident, you would simply betray your unquestioned belief in it. Indeed, any attempt to logically prove the validity of logic would just make the circularity of the whole thing rather explicit, wouldn't it?" What would Langan's comment on this be?