An outline for Logic Systems through time
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The flowering of logic systems began with the Greeks.
Western Europe and the Islamic world borrowed from this
treasure chest of logic. In modern times logics based on Greek logic have spread through the entire world.
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Conditional logic - Megarian School - Euclid of Megara student of Socrates
Euclid of Megara 435-365 BC
Conditional logic is the "if - then " logic.
Sylogistic logic - Peripatetics/Lyceum-Athens Aristotle
Aristotle 384–322 BC
Aristotle invented the famous syllogism which is actually a system of logic.
Early axiomatic logic
Euclid 300 BC
Euclid of Alexandria did geometry with axiomatic logic.
From a small number of axioms (assumptions) he defined and could prove planar geometry
Early Propositional and Conditional logic - Stoics
Chrysippus 279 – 206 BC
Built and refined Megarian logic.
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Western Europe built upon Greek logical systems
The Romans borrowed much of Greek Philosophy and later the Western Europeans borrowed Greek Philosophy from Byzantium ( Eastern
Roman) and the Islamic world.
Western Europe's Mathematical logic
One way to look at logic is that it can be calculated.
Starting with Boole, Western Europe mathematics becomes involved with logic.
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Early forms of mathematical logic
Leibniz 1646-1716
Much of Leibniz logical work was not published until the twentieth century.
Combinatory logic - Boolean Algebra
Boole 1815-1864
Boolean Algebra was early mathematical system of logic which could do combinatory logic.
Today this system of logic is extensively used in Computer Engineering, Computer Science and Control Engineering.
Set Theory
Georg Cantor 1845 – 1918
Logical systems could be interpreted using set theory and formed a mathematical basis for modern
logic.
Axiomatic arithmetic logic
Peano 1858 – 1932
Peano created axioms using set theory to explain arithmetic.
Formal logic
Frege 1848-1925
Invented modern propositional and predicate logic to create logical system for arithmetic.
He also used Peano's axioms and set theory.
Principia Mathematica
Russell Russell 1872 – 1970 and Whitehead 1861 – 1947
Basically takes what Frege did and fixed Russell's paradox. This
starts a few philosophical schools - Logical Atomism, Logical Positism and Analytical Philosophy. Also several famous
philosphers and mathemacians made their start with Principia Mathematica such as Wittgenstein. Was supposed to
be the basis of all mathematics and philosophy until Godel came along.
Propositional logic
Emil Post 1897 – 1954
Proved propositional logic of the Principia used was consistent and complete.Consistent means there are no
contradictions. Completeness means that either a proof or disproof exists for every theorm.
Predicate logic
David Hilbert 1862 – 1943 William Ackerman 1896 – 1962
Hilbert and Ackerman proved that Predicate logic was consistent.
Predicate logic
Kurt Godel 1906 – 1978
Godel proved that Predicate logic was complete.
Principia Mathematica is incomplete
Kurt Godel 1906 – 1978
Godel proved that using Peao's axioms, set theory in the Principia as a basis for mathematics was incomplete.
Nu recursion
Kurt Godel 1906 – 1978
Godel's Nu recursion system was Turing complete and could potentially solve Hilberts decidability problem.
Decidability means that there's an algorithm for finding a proof or disproof.
Hilbert's decidability question: does there exist a “definite method” that, when given any
possible statement in mathematics, can decide whether that statement is true or false?
Lambda calculus
Alonso Church 1903 – 1995
Church gets credit for solving Hilberts decidability problem with lambda calculus. His lambda
calculus proved it was not decideable. Lambda calculus was later a basis for functional programming.
Universal Turing Machine
Alan Turing 1912 - 1954
Turing also solves Hilberts decidability problem. The Turing Machine proved it was not decideable with the halting
phenomenon. His system was the most intuitive and useful and is used by Computer Science.
Anything that is equivalent to a Universal Turing Machine is considered a theorectical computer such
as lambda calculus, nu recursion etc.
Turing Machines are state machines also known as automata
Other state machines which have more practical uses are Finite State Automota and Push Down Automota.
Finite State Machines
Warren McCulloch 1898 - 1969 Walter Pitts 1923 - 1969
McCulloch was a Psychologist and Pitts was a self taught logician who met with an interdisciplinary team interested
in the mind and computers. They were first to define finite automata.
Artificial Neural Networks
Warren McCulloch 1898 - 1969 Walter Pitts 1923 - 1969
McCulloch was a Psychologist and Pitts was a self taught logician who met with an interdisciplinary team interested
in the mind and computers. They created a computational model for neural networks. These loosely model the neurons in the
human brain. These neural networks allow computers to do pattern recognition and allow the solving of problems in
AI, machine learning and deep learning.
Chomsky's Hierarchy
Noam Chomsky 1928 -
Chomsky believes Humans acquire early language very quickly because they have a language acquition system equivalent to
a Universal Turing Machine in their brain. However, apart from linquistic theory, this Hieracrchy is very useful to the study of
logical systems and automata.
Grammar Languages Automaton
Type-0 Recursively enumerable Turing machine
Type-1 Context-sensitive Linear-bounded non-deterministic Turing machine
Type-2 Context-free Non-deterministic pushdown automaton
Type-3 Regular Finite state automaton