# Frases de Alan Turing

## Alan Turing

**Data de nascimento:** 23. Junho 1912**Data de falecimento:** 7. Junho 1954**Outros nomes:**एलन ट्यूरिंग,Алан Матисон Тьюринг

Alan Mathison Turing OBE foi um matemático, lógico, criptoanalista e cientista da computação britânico. Foi influente no desenvolvimento da ciência da computação e na formalização do conceito de algoritmo e computação com a máquina de Turing, desempenhando um papel importante na criação do computador moderno. Foi também pioneiro na inteligência artificial e na ciência da computação. É conhecido como o pai da computação.

Durante a Segunda Guerra Mundial, Turing trabalhou para a inteligência britânica em Bletchley Park, num centro especializado em quebra de códigos. Por um tempo ele foi chefe do Hut 8, a seção responsável pela criptoanálise da frota naval alemã. Planejou uma série de técnicas para quebrar os códigos alemães, incluindo o método da bomba eletromecânica, uma máquina eletromecânica que poderia encontrar definições para a máquina Enigma.

Após a guerra, trabalhou no Laboratório Nacional de Física do Reino Unido, onde criou um dos primeiros projetos para um computador com um programa armazenado, o ACE. Posteriormente, Turing se interessou pela química. Escreveu um artigo sobre a base química da morfogênese e previu reações químicas oscilantes como a Reação de Belousov-Zhabotinsky, que foram observadas pela primeira vez na década de 1960.

A homossexualidade de Turing resultou em um processo criminal em 1952, pois atos homossexuais eram ilegais no Reino Unido na época, e ele aceitou o tratamento com hormônios femininos e castração química, como alternativa à prisão. Morreu em 1954, algumas semanas antes de seu aniversário de 42 anos, devido a um aparente autoadministrado envenenamento por cianeto, apesar de sua mãe terem considerado sua morte acidental. Em 10 de setembro de 2009, após uma campanha de internet, o primeiro-ministro britânico Gordon Brown fez um pedido oficial de desculpas público, em nome do governo britânico, devido à maneira pela qual Turing foi tratado após a guerra. Em 24 de dezembro de 2013, Alan Turing recebeu o perdão real da rainha Elizabeth II, da condenação por homossexualidade.

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### Citações Alan Turing

### „I am not very impressed with theological arguments whatever they may be used to support. Such arguments have often been found unsatisfactory in the past.“

— Alan Turing

Context: I am not very impressed with theological arguments whatever they may be used to support. Such arguments have often been found unsatisfactory in the past. In the time of Galileo it was argued that the texts, "And the sun stood still... and hasted not to go down about a whole day" (Joshua x. 13) and "He laid the foundations of the earth, that it should not move at any time" (Psalm cv. 5) were an adequate refutation of the Copernican theory.
pp. 443-444.

### „Mathematical reasoning may be regarded rather schematically as the exercise of a combination of two facilities, which we may call intuition and ingenuity.“

— Alan Turing

Context: Mathematical reasoning may be regarded rather schematically as the exercise of a combination of two facilities, which we may call intuition and ingenuity. The activity of the intuition consists in making spontaneous judgements which are not the result of conscious trains of reasoning... The exercise of ingenuity in mathematics consists in aiding the intuition through suitable arrangements of propositions, and perhaps geometrical figures or drawings.
"Systems of Logic Based on Ordinals," section 11: The purpose of ordinal logics (1938), published in Proceedings of the London Mathematical Society, series 2, vol. 45 (1939)
In a footnote to the first sentence, Turing added: "We are leaving out of account that most important faculty which distinguishes topics of interest from others; in fact, we are regarding the function of the mathematician as simply to determine the truth or falsity of propositions."

### „These questions replace our original, "Can machines think?"“

— Alan Turing

Context: "Can machines think?"... The new form of the problem can be described in terms of a game which we call the 'imitation game." It is played with three people, a man (A), a woman (B), and an interrogator (C) who may be of either sex. The interrogator stays in a room apart front the other two. The object of the game for the interrogator is to determine which of the other two is the man and which is the woman. He knows them by labels X and Y, and at the end of the game he says either "X is A and Y is B" or "X is B and Y is A." The interrogator is allowed to put questions to A and B... We now ask the question, "What will happen when a machine takes the part of A in this game?" Will the interrogator decide wrongly as often when the game is played like this as he does when the game is played between a man and a woman? These questions replace our original, "Can machines think?"

### „The majority of them seem to be "sub-critical," i.e., to correspond in this analogy to piles of sub-critical size. An idea presented to such a mind will on average give rise to less than one idea in reply. A smallish proportion are super-critical. An idea presented to such a mind may give rise to a whole "theory" consisting of secondary, tertiary and more remote ideas.“

— Alan Turing

Context: Another simile would be an atomic pile of less than critical size: an injected idea is to correspond to a neutron entering the pile from without. Each such neutron will cause a certain disturbance which eventually dies away. If, however, the size of the pile is sufficiently increased, the disturbance caused by such an incoming neutron will very likely go on and on increasing until the whole pile is destroyed. Is there a corresponding phenomenon for minds, and is there one for machines? There does seem to be one for the human mind. The majority of them seem to be "sub-critical," i. e., to correspond in this analogy to piles of sub-critical size. An idea presented to such a mind will on average give rise to less than one idea in reply. A smallish proportion are super-critical. An idea presented to such a mind may give rise to a whole "theory" consisting of secondary, tertiary and more remote ideas. Animals minds seem to be very definitely sub-critical. Adhering to this analogy we ask, "Can a machine be made to be super-critical?"
p. 454.

### „The view that machines cannot give rise to surprises is due, I believe, to a fallacy to which philosophers and mathematicians are particularly subject. This is the assumption that as soon as a fact is presented to a mind all consequences of that fact spring into the mind simultaneously with it. It is a very useful assumption under many circumstances, but one too easily forgets that it is false.“

— Alan Turing

Context: The view that machines cannot give rise to surprises is due, I believe, to a fallacy to which philosophers and mathematicians are particularly subject. This is the assumption that as soon as a fact is presented to a mind all consequences of that fact spring into the mind simultaneously with it. It is a very useful assumption under many circumstances, but one too easily forgets that it is false. A natural consequence of doing so is that one then assumes that there is no virtue in the mere working out of consequences from data and general principles.
p. 451.

### „Science is a differential equation. Religion is a boundary condition.“

— Alan Turing

Epigram to Robin Gandy (1954); reprinted in Andrew Hodges, Alan Turing: the Enigma (Vintage edition 1992), p. 513.