Philosophical Antecedents

Philosophical and Intellectual Antecedents

Aristotle (3rd Century BC): Matter vs. Form An early example of abstraction. Given a statue we can distinguish the matter (bronze) from the form (human). An early antecedent of data abstraction. Given a data structure, we can distinguish its representation (linked list) from its form (a stack). In AI, we view computation as manipulation of symbols. Computers manipulate patterns (integers, lists) that are represented in electronic materials. The human brain manipulates patterns (ideas, concepts) that are represented in neurons.
Aristitotle's Logic. Invented the syllogism.
```
All humans are mortal.
Socrates is human.
Therefore, Socrates is mortal.
```
Any argument that has this syllogistic form is a valid argument, which means that if its premises are true, then its conclusion is true.
Copernicus and Galileo (16th Century): Reality vs. Appearance. Heliocentric theory of the universe (reality) is based on scientific evidence whereas the geocentric theory is based on appearance.
Descartes (17th Century): Cogito ergo sum. I think therefore I am. Mind vs. Matter. Is the mind (consciousness) distinct from matter (brain)? If so, how do they interact? Importance for AI: It may be useful to distinguish the mental processes (ideas, reason, concepts) from their underlying material representations (the brain, a computer).
Thomas Hobbes (17th Century): Cognition is computation. Thinking can be characterized through logic and mathematics.
Leibniz (17th Century) First system of formal logic. First to attempt a mechanical calculating machine.
Boole (19th Century): Boolean algebra -- the mathematical formalization of the laws of logic. (The Laws of Thought).
Frege (19th Century): Developed the first order predicate calculus.
```
For all x(Human(x) --> Mortal(x))
Human(socrates)
Therefore Mortal(socrates)
```
This is a formalization the Aristotelian syllogism.
Russell and Whitehead (20th Century) (Principia Mathematica): An attempt to reduce all mathematics to logic axioms. That is, axioms and theorems would be treated as a purely formal, syntactic, system. Proofs of mathematical theorems would be derived independently of their meaning (semantics).
Alfred Tarski (20th Century) Developed a formal theory of reference and truth which served as a foundation of theories used to characterize the semantics of programming language.
Alan Turing (1940s) Turing machine, an abstract model of a digital computer was used to determine the limits of computation. That is, the limits of what can be computed by means of an algorithm. Turing proved that all calculable functions could be computed by a universal Turing machine. He also proved that there are uncompatable problems (e.g., the halting problem).
Alan Turing (1950) The Turing Test, a proposal for how to solve the problem of determining whether a machine could be intelligent.
Alonzo Church (1950s) Church-Turing Thesis (unprovable) Anything that can be calculated by means of an algorithm, can be calculated by a computer. This is often interpreted to mean that a computer can do (or simulate) anything that a human brain can compute. That is, that the human brain is a computer.