最近，一位朋友向我提到了约翰·L·卡斯蒂（John L. Casti）的《剑桥五重奏：科学推测之作》（Perseus Books，1998），因为艾伦·图灵在这部有关机器智能的虚构对话中扮演了重要角色。

背景是这样的：1949 年，斯诺（C.P. Snow ）想就机器智能的可能性和潜力向英国政府提供建议，因此他在剑桥的家中举办了一场晚宴，邀请了四位嘉宾讨论这些问题：图灵、哲学家维特根斯坦（Ludwig Wittgenstein）、遗传学家霍尔丹（J. B. S. Haldane）和物理学家薛定谔（Edwin Schrödinger）。卡斯蒂在七章中讲述了这场想象中的对话，这些章节对应于晚餐的菜肴（雪利酒、汤、鱼、肉、沙拉、甜点、雪茄和白兰地），结果是对与人工智能和人类意识相关的一些哲学概念进行了有趣的介绍。

虽然传统上哲学对话是典型人物，如西塞罗（Cicero）、伽利略（Galileo）和休谟（Hume）的对话，而不是实际的历史人物，但是哲学对话是一种历史悠久的体裁。这些人物无疑使《剑桥五重奏》比原本更引人注目，我们看到衣衫褴褛的图灵在描述他的研究和想法时经常激动地结结巴巴，而维特根斯坦已经患有致命的癌症，但他还是登上舞台发表他深刻的言论。

辩论主要在图灵和维特根斯坦之间进行，斯诺担任主持人。卡斯蒂为什么特别把薛定谔和霍尔丹拉入争论并不总是很清楚——尽管薛定谔有时会引入东方宗教观点，霍尔丹则对苏联的李森科（Lysenko ）悲剧表示哀叹。

卡斯蒂在作者注中警告我们，他所吸收的思想是在 1949 年以后出现的，听到维特根斯坦采用了约翰·塞尔（John Searle）著名的中文房间论证的略加修改的版本，以及图灵描述通常归因于诺姆·乔姆斯基（Noam Chomsky）的思想，确实令人震惊：“假设”，卡斯蒂的图灵说，“我们的大脑中有一个由进化赋予我们的结构，专门用于语言，一种语言’器官’，如果你愿意的话。”（第 121 页）我根本不知道图灵对语言的分析，更不用说像这样的了。

然而，最让我困扰的时代错误是艾伦·图灵描述了他的1936 年计算机在“停机问题”方面的进展（第 42 页）。如果我对即将出版的《图灵注释》(The Annotated Turing )一书抱有任何希望，那就是希望读者能够理解图灵的原始机器与 Stephen Kleene 的《元数学导论》（1952 年）和 Martin Davis 的《可计算性和不可解性》（1958 年）中重新表述的机器之间的区别，图灵去世四年后，“停机问题”一词首次出现在《可计算性和不可解性》一书中。

《剑桥五重奏》中的时代错误加剧了这种对话，以至于对话听起来不像是在 1949 年发生的。据我所知，在 1949 年，仍然有很多人坚持身心二元论——认为人类大脑的物理组成不足以解释心灵的所有功能。事实上，正是在 1949 年，吉尔伯特·赖尔（Gilbert Ryle）的《心灵概念》出版，才帮助瓦解了西方思想中残留的二元论痕迹。

如果心灵中有一些“额外”的东西，无法用大脑的生物机制来解释，那么关于机械智能的争论基本上就结束了。当然，在 1949 年，在真正的讨论开始之前，有必要摒弃二元论。然而，在《剑桥五重奏》中，二元论仅在第 138 页被提及，当时霍尔丹宣布他的信念是心灵“是一个与普通物质系统相互作用的独立实体”，斯诺很快就打断了这种“形而上学的推测”。

如果我们要把五个人放在一个房间里，其中大多数人在现实生活中从未见过面（图灵曾参加过 1939 年在剑桥举行的维特根斯坦数学基础讲座），为什么不把库尔特·哥德尔（Kurt Gödel）也加入进来呢？哥德尔作为二元论者几乎和柏拉图主义者一样出名——参见贾德森·C·韦伯（Judson C. Webb）在《库尔特·哥德尔文集》第二卷（牛津大学出版社，1990 年）第 292-304 页中对哥德尔 1972 年“言论”的注释——因此哥德尔的出席可能提供了另一个有趣的视角。

不过，我喜欢《剑桥五重奏》，它与现在围绕着艾伦·图灵这位迷人人物的许多其他文化遗产汇合一起了。

原文：

https://www.charlespetzold.com/blog/2008/05/120214.html

Reading Casti’s “The Cambridge Quintet”

A friend mentioned John L. Casti's The Cambridge Quintet: A Work of Scientific Speculation (Perseus Books, 1998) to me recently because Alan Turing plays a major role in this fictional dialogue concerning machine intelligence.

The premise is this: In 1949, C.P. Snow wants to advise the British government on the possibilities and potentials of machine intelligence, so he hosts a dinner party at his home in Cambridge with four guests to discuss the issues: Turing, philosopher Ludwig Wittgenstein, geneticist J. B. S. Haldane, and physicist Edwin Schrödinger. Over seven chapters corresponding to the courses of the dinner (sherry, soup, fish, meat, salad, dessert, and cigars and brandy), Casti narrates this imagined conversation. The result is an entertaining introduction to some of the philosophical concepts associated with artificial intelligence and human consciousness.

The philosophical dialogue is a time-honored genre, although traditionally it's populated by character types (such as in the dialogues of Cicero, Galileo, and Hume) rather than actual historical personages. The personalities definitely make The Cambridge Quintet more compelling than it would have been otherwise. We get to see the rumpled Turing often excitedly stuttering when describing his research and ideas, and Wittgenstein already suffering from the cancer that will kill him but taking the stage to deliver his profound pronouncements.

The debate is primarily between Turing and Wittgenstein, with Snow playing the moderator. It's not always clear why Casti specifically brought Schrödinger and Haldane into the fray — although Schrödinger sometimes introduces a Eastern religious perspective, and Haldane bemoans the Lysenko travesty in the U.S.S.R.

Casti warns us in the Author's Note that he incorporates ideas that arose much later than 1949, and it is indeed startling to hear Wittgenstein adopt a lightly altered version of John Searle's famous Chinese Room argument, and for Turing to describe ideas normally attributed to Noam Chomsky: "Suppose," Casti's Turing says "there is a structure in our brains given to us by evolution that is specialized just for language, a kind of language 'organ", if you like." (pg. 121) I know of no analysis of language by Turing at all, let alone one like this.

The anachronism that bothered me the most, however, was Alan Turing describing his 1936 computing machines in terms of the "halting problem" (pg. 42). If there is any hope at all I have for my forthcoming book The Annotated Turing it is for readers to appreciate the difference between Turing's original machines and the reformulated machines in Stephen Kleene's Introduction to Metamathematics (1952) and Martin Davis's Computability and Unsolvability (1958), which is where the term "halting problem" first appeared in print four years after Turing's death.

The anachronisms in The Cambridge Quintet compound to the point where the conversation just doesn't sound like it took place in 1949. It is my understanding that in 1949 there were still many people who held to mind/body dualism — the belief that the physical composition of the human brain is insufficient to account for all the functionality of the mind. Indeed, it was in 1949 that Gilbert Ryle's Concept of Mind was published that helped dismantle vestiges of dualism that remained in Western thought.

If the mind has something "extra" that can't be accounted for by the biological machinery of the brain, then the debate about mechanical intelligence is basically over. Surely in 1949 it would have been necessary to dispense with dualism before the real discussion got underway. Yet in The Cambridge Quintet dualism is only alluded to on page 138 when Haldane announces his belief that mind "is a separate entity interacting with ordinary material systems." Snow quickly cuts off this "metaphysical speculation. »

If we're going to put five people in a room, most of whom never met each other in real life (Turing had attended Wittgenstein 1939 lectures at Cambridge on the Foundations of Mathematics), why not bring Kurt Gödel into the mix? Gödel was almost as famous a Dualist as he was a Platonist — see Judson C. Webb's notes on a 1972 "remark" by Gödel in Kurt Gödel, Collected Works, Volume II (OUP, 1990), pgs. 292-304 — so Gödel's attendance might have provided another interesting perspective.

Still, I enjoyed The Cambridge Quintet, and it joins the many other cultural artifacts that now surround the fascinating figure of Alan Turing.