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88 lines
8.5 KiB
88 lines
8.5 KiB
The Kindelia Manifesto
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What is the true nature of computation? A hundred years ago, humanity answered that very question, twice. In 1936, Alan
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invented the Turing Machine, which, highly inspired by the mechanical trend of the 20th century, distilled the common
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components of early computers into a single universal machine that, despite its simplicity, was capable of performing
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every computation conceivable. From simple numerical calculations to entire operating systems, this small machine could
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compute anything. Thanks to its elegance and simplicity, the Turing Machine became the most popular model of
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computation, and served as the main inspiration behind every modern processor and programming language. C, Fortran,
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Java and Python, are languages based on a procedural mindset, which is highly inspired by Turing's invention.
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Yet, the Turing Machine wasn't the only model of computation that humanity invented. Albeit a less known history, also
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in 1936, and in a completely independent way, Alonzo Church invented the Lambda Calculus, which distilled the common
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components - not of machines, but of different branches of math - into a single universal language that was capable of
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modeling every mathematical theory. What was surprising, though, is that this language, unexpectedly, could also perform
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computations. The same algorithms that could be computed by Turing Machines procedurally, could also be computed by the
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Lambda Calculus, through symbolic manipulations. The idea of using the Lambda Calculus for computations inspired the
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creation of an entire new branch of programming, which we call the functional paradigm. Haskell, Clojure, Elixir and Agda,
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are languages based on the functional mindset, which is highly inspired by Church's invention.
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If both, Turing Machines (and procedural languages) and the Lambda Calculus (and functional languages), are capable of doing
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computations, then which mindset is the "right one"? When it comes to raw capabilities, neither. Still on the 20th century, it
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was proven that, when it comes to computability, Turing Machines and the Lambda Calculus are equivalent. Every problem
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that one can solve, can also be solved by the other. That insight is known as the Church-Turing thesis, which
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essentially states that computers are capable of emulating each-other. If that was completely true, then the choice
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wouldn't matter. After all, if, for example, every programming language is capable of solving the same set of problems,
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then what is the point in making a choice?
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Yet, while the Church-Turing hypothesis makes a statement about computability, it says nothing about computation. In
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other words, a model can be inherently less efficient than other. Historically, procedural languages such as C and
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Fortran have consistently outperformed the fastest functional languages, such as Haskell and Ocaml. Yet, languages
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like Haskell and Agda provide abstractions that make entire classes of bugs unrepresentable. Historically, the
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functional paradigm has been more secure. Of course, these factors can vary greatly, but the point is that this notion
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of equivalence is limited, and there are impactful differences.
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In 1983, Stephen Wolfram introduced the Rule 110, an elementary cellular automaton that has been shown to be as capable
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as both. Wolfram argues that this model is of fundamental importance for math and physics, and that a new kind of science should emerge from
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its study. These claims were met with harsh skepticism; after all, if all models are equivalent, what is the point?
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Yet, we've just stablished that, while equal in capacity, different models result in different practical outcomes.
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Perhaps there isn't a new branch of science to emerge from the study of alternative models of computation, but what
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about the design of processors and programming languages?
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A model of computation has a significant impact on the way we design our languages, and several of their drawbacks can
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be traced down to limitations of the underlying model. For example, the parallel primitives of the procedural paradigm,
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mutexes and atomics, provide a contrived, complex solution to multi-threaded synchronization. As a result, parallelism
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is generally considered hard, and programmers still write sequential code by default. Similarly, security isn't natural
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to the procedural paradigm. Global state, mutable arrays and loops generate an explosion of possible execution paths,
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edge cases and off-by-one errors that make absolute security all but impossible. Even highly audited code, such as
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OpenSSL, is often compromised by out-of-bounds exploits. The functional paradigm handles both issues much better: there
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is an enourmous amount of inherent parallelism on functional programs, and logic-based type systems make entire classes
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of bugs unrepresentable. But if that is the case, then why functional programs are still mostly single-threaded, and
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bug-ridden? And why isn't the functional paradigm more prevalent?
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A strong factor, we argue, is performance issues. As much as the Turing Machine, and, thus, the procedural paradigm as a
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whole, is inadequate for parallelism and security, the Lambda Calculus, and the functional paradigm as a whole, is
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inadequate for efficient computations. The fundamental operation of the Lambda Calculus, substitution, may trigger an
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unbounded amount of copies of an unboundedly large argument. Because of that, it can not be performed in a bounded
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amount of steps, and, thus, there isn't a physical mapping of substitution to real-world physical processes. In other
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words, substitution isn't an atomic operation, which prevents us from creating efficient functional processors and
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runtimes. Attempts to solve the issue only pushed it into other directions, such as the need of shared references, which
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inhibit parallelism, or garbage collection, which isn't atomic. The failure of the functional paradigm to achieve
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satisfactory efficiency impacted its popularity, which, in turn, lead to tools like formal proofs to never catch up.
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This raises the question: is there a model of computation, which, like the Turing Machine, has a reasonable physical
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implementation, and yet, like the Lambda Calculus, has a robust logical interpretation? In 1997, Yves Lafont proposed a new
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alternative, the Interaction Combinators, on which substitution is broken down into 2 fundamental laws: commutation,
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which creates and copies information, and annihilation, which observes and destroys information. In a sense, this may
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resemble SKI combinators, but that isn't a good analogy, since SKI combinators still include non-atomic operations: K
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may erase an unboundedly large structure, and S may copy an unboundedly large structure. The charm, and elegance, of the
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Interaction Combinators is that its reduction laws are truly atomic: each operation can be completed in a constant
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amount of steps, and has a clear physical mapping. Not only that, they're inherently parallel, in the same sense that
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the Lambda Calculus has been claimed to be, in theory, but without the issues that let it to be, in practice.
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Interestingly, every aspect that is considered good in other models of computation, is present on Interaction
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Combinators, while negative aspects are completely absent. Moreover, both the Lambda Calculus and the Turing Machine can
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be efficiently emulated by the Interaction Combinators, while the opposite isn't true. This suggests that, while the 3
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systems are equivalent in terms of computability, the Interaction Combinators are more capable in terms of computation.
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Under certain point of view, one could argue that both the Turing Machine and the Lambda Calculus are slight distortions
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of this fundamental model, caused by human creativity, due to our historical intuitions regarding machines and
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mathematics. Perhaps machines and substitutions aren't as fundamental as we think, and some alien civilization has
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developed all its mathematical theories and computers based on annihilation and commutation, with no references to the
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Lambda Calculus, or the Turing Machine.
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We, at the Kindelia Foundation, hold the view that Interaction Combinators are a more fundamental model of computation,
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and, consequently, that computers, processors and programming languages inspired by them would offer tangible benefits
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compared to the ones we built based on Turing Machines and the Lambda Calculus. The Kindelia Foundation was created to
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research this new model of computation, and, through the different mindset it brings, catch insights that will let us
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produce groundbreaking technology that will push humanity towards the next level of computational maturity.
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