卡尔·皮尔逊Karl Pearson

卡尔·皮尔逊的母亲Fanny Smith和父亲William Pearson都出身于约克郡的家庭。William是内殿律师学院[26]的律师：-

他能力出众，拥有非凡的智力和体力，对历史研究有浓厚的兴趣，这些特质在他儿子身上也有所体现。

William和Fanny给他们的第二个孩子取名为Carl，他一直使用这个名字，直到大约23岁时将拼写改为皮尔逊。在本文中，我们将称他为皮尔逊或皮尔逊。

皮尔逊与他的一个哥哥和一个妹妹在一个中上阶层家庭中长大。在家接受教育到九岁后，他被送到伦敦的大学学院学校。他在那里学习到十六岁，但随后因病被迫离开。家里请了一位私人教师在家教他，他于1875年参加了剑桥奖学金考试，在考试中获得第二名，赢得了国王学院的奖学金。

在剑桥，他师从乔治·加布里埃尔·斯托克斯、詹姆斯·克拉克·麦克斯韦、阿瑟·凯莱和威廉·伯恩赛德。他的辅导老师也许是所有剑桥辅导老师中最著名的，即爱德华·约翰·劳思。他谈到自己的本科岁月时说（见[3]）：-

在剑桥，我在爱德华·约翰·劳思、乔治·加布里埃尔·斯托克斯、阿瑟·凯莱和詹姆斯·克拉克·麦克斯韦的指导下学习数学，但阅读了关于斯宾诺莎的论文。

但这对皮尔逊来说是非常幸福的日子[22]：-

在友谊中有快乐，在争论中有快乐，在教练的教导中有快乐，在数学、哲学和宗教中寻找新光芒也有快乐。

正如他在这些引文中所表明的，他在剑桥的学习异常广泛。他读过歌德、但丁和卢梭，读过宗教思想史，并喜欢与道德哲学的学生就他们的学科进行辩论。

皮尔逊从不是一个接受权威的人，这一点在他剑桥的本科岁月中表现得淋漓尽致。当时，神学讲座和礼拜堂出席是强制性的。皮尔逊对宗教深感兴趣，却憎恨这些活动的强制性。他成功地说服校方修改了大学规章，使神学讲座不再强制出席；赢得这场斗争后，他在父亲的帮助下又打了第二场关于强制礼拜堂的斗争。获胜后，他继续出席礼拜堂，令大学当局感到惊讶，但当然，对皮尔逊来说，自愿出席和强制出席之间有着天壤之别。

他于1879年从剑桥大学毕业，在数学荣誉学位考试中获得数学荣誉学位考试一等及格者（Wrangler）（意味着他在获得一等学位的人中排名第三）。随后他前往德国，在海德堡大学学习。在那里，他跟随G H Quincke学习物理学，跟随Kuno Fischer学习形而上学。接着他访问了柏林大学，在那里他听了著名生理学家Émile du Bois-Reymond关于达尔文主义的讲座（Émile是数学家Paul du Bois-Reymond的兄弟）。他在柏林学习的其他科目包括由海因里希·布伦斯和Mommsen教授的罗马法、中世纪和16世纪德国文学以及社会主义。他深受此时所修课程的影响，并且在德国文学方面变得足够专业，以至于剑桥大学德语系向他提供了一个职位。1880年返回英国后，皮尔逊首先去了剑桥[3]：-

回到剑桥后，我在工程车间工作，但为中古语言荣誉学位考试制定了中古高地德语和古高地德语的日程表。

他的第一本书The New Werther就是在这时出版的。在书中，皮尔逊清楚地表明了他为什么学习如此多不同的科目（例如见[17]或[26]或The New Werther):-

我从科学冲向哲学，又从哲学冲向我们的老朋友诗人；然后，因过多的理想主义而过度疲惫，我想象自己在回归科学时变得实际。你是否曾试图构想世界上所有值得知道的事物——宇宙中没有一门学科不值得研究？文学的巨匠，多维空间的奥秘，路德维希·玻尔兹曼和Crookes试图穿透自然本身的实验室，康德的宇宙理论，以及胚胎学的最新发现，连同它们关于生命发展的奇妙故事——那是多么广阔无垠，超出我们的把握！……人类似乎正处于一项新的辉煌发现的边缘。艾萨克·牛顿为简化行星运动所做的一切，现在必须用来将数学物理的各种孤立理论统一为一个整体。

尽管他在这段话中表达了自己的感受，皮尔逊还是决定学习法律，以便像他父亲一样，取得律师资格。再次引用皮尔逊自己的叙述[3]：-

来到伦敦后，我在林肯律师学院的事务所里研读法律，起草卖据，并取得了律师资格，但我也通过讲课来变换法律研究的内容：在巴恩斯讲热学，在汉普斯特德讲马丁·路德，在星期天于苏活区周边的革命俱乐部讲拉萨尔和马克思。

尽管在1882年取得律师资格，皮尔逊从未执业。在1882至1884年间，他在伦敦各地就广泛的主题讲课，如德国社会生活、马丁·路德的影响以及历史主题。他还撰写随笔、文章和评论，并在国王学院和伦敦大学学院代授数学教授的课程。

他的大部分职业生涯都在伦敦大学学院度过，1885年他被任命为应用数学讲席，成为戈德史密斯教授。他以前的一位学生在[3]中写道：-

他不是一个“教科书式”的教师，他能以比我后来所知的任何数学讲师都更轻松、更短的时间灌输对一门学科基本原理的理解。他的外貌引人注目：典型的希腊运动员，五官精致，体格健美。……他是一个固执的争论者，但在任何个人讨论中，他幽默的闪烁眼神令人解除戒备。

从1884年到1890年，皮尔逊成果丰硕。除了讲授静力学、动力学和力学，他还完成了威廉·金顿·克利福德的The Common Sense of the Exact Sciences未完成的第一卷（1885年出版），完成并编辑了艾萨克·托德夯特的History of the Theory of Elasticity写了一半的第一卷，开始着手艾萨克·托德夯特几乎尚未开始的第二卷，并发表了许多应用数学论文。他还讲授The Ethic of Free Thought，并就若干历史主题进行研究，如西方基督教的演变。1885年，他是男女俱乐部的创始成员，该俱乐部致力于讨论男女在社会中的角色，在俱乐部的会议上他遇到了玛丽亚·夏普。他们于1890年结婚，育有三个孩子；伊根·皮尔逊（生于1895年）继承了父亲的职业，还有两个女儿：比埃贡大三岁的西格丽德·洛蒂蒂娅和比埃贡小三岁的海尔加·夏普。

值得停下来想一想，皮尔逊 被认为是统计学的奠基人之一，然而到了 1890 年，这位 33 岁的应用数学教授虽然在众多领域享有很高声誉，却仍未开始研究统计问题。正如 Aldrich 在 [6] 中所写：-

……他对统计方法论的贡献盖过了他对任何实质性领域的贡献。他的统计贡献可以分为整理数值事实的方法——单变量和多变量——估计和检验。

两件事改变了他职业生涯的走向。第一件是 弗朗西斯·高尔顿 于 1889 年出版了他的著作 Natural Inheritance。第二件是 拉斐尔·韦尔登 于 1890 年被任命为伦敦大学学院的动物学教授。Walker 在 [26] 中写道：-

皮尔逊 与 拉斐尔·韦尔登 之间很快建立起的亲密私人友谊对科学的重要性，当时两人都三十出头，怎么夸大也不为过。拉斐尔·韦尔登 提出的问题推动 皮尔逊 做出了他一些最重要的贡献。

通过 拉斐尔·韦尔登 和 弗朗西斯·高尔顿 的书，皮尔逊 对发展用于研究遗传和进化过程的数学方法产生了兴趣。从 1893 年到 1912 年，他写了 18 篇题为 Mathematical Contributions to the Theory of Evolution 的论文，其中包含了他最有价值的工作。这些论文包含了对回归分析、相关系数的贡献，并包括统计显著性的卡方检验（1900 年）。他的卡方检验是为了试图使正态分布不再处于中心地位而提出的。

他的书 The Grammar of Science（1892 年）之所以引人注目，是因为它预见了相对论的一些思想。它内容广泛，并试图将科学的影响扩展到各个方面。皮尔逊 在 1893 年创造了“标准差”这个术语。他的工作受到了 弗朗西斯·伊西德罗·埃奇沃思 工作的影响，而他又反过来影响了 犹勒 的工作。

皮尔逊 与 拉斐尔·韦尔登 和 弗朗西斯·高尔顿 共同创办了统计学期刊 Biometrika。这件事的起因是他在 1900 年向 皇家学会 提交了一篇论文，他于 1896 年当选为该会会士，并于 1898 年获得其达尔文奖章。这篇论文研究了遗传，并通过对大量收集数据的数学分析进行论证。然而，Royal Society 的生物学家并不准备接受基于数学分析的生物学结论。拉斐尔·韦尔登 在 1900 年 11 月 16 日给 皮尔逊 的一封信中建议，通过创办他们自己的期刊来解决这类论文发表的问题。皮尔逊 对此很热情，并建议将期刊命名为 Biometrika。第一卷于 1901 年 10 月出版，皮尔逊 担任其编辑，他一直担任这一角色直到 35 年后去世。

大约从 1906 年起，皮尔逊 投入了大量精力筹建一个研究生中心。他这样做（见 [17]）：-

……使统计学成为应用数学的一个分支，拥有自身的技术和术语体系，把统计学家培养成科学工作者……并总体上把这个国家的统计学从业余爱好者和争论者的游乐场转变为一门严肃的科学分支，任何人若不经过充分训练就无法有效运用它，正如不懂数学就无法运用微积分一样。

他是第一位弗朗西斯·高尔顿优生学教授，从1911年到1933年担任该讲席。弗朗西斯·高尔顿于1904年建立了优生学档案办公室，1906年他让皮尔逊负责。皮尔逊已经在管理生物测量实验室，1911年这两个实验室合并为大学学院的应用统计系。弗朗西斯·高尔顿曾表示希望皮尔逊被授予该讲席，从而成为新系的负责人。这样做时，皮尔逊放弃了他的Goldsmid讲席。

皮尔逊与罗纳德·费希尔有过一场长期、激烈且非常公开的争论。起初，在皮尔逊于1914年9月收到罗纳德·费希尔提交发表的一篇论文手稿后，他们交换了友好的信件。皮尔逊最初的回应是说（见[18]）：-

我非常衷心地祝贺你弄出了实际的分布形式……如果分析是正确的——这似乎极有可能——我将很高兴在Biometrika上发表这篇论文。

一周后[18]又写道：-

我现在已通读了你的论文，认为它标志着明显的进步。

皮尔逊随后提议让他在弗朗西斯·高尔顿实验室的工作人员研究罗纳德·费希尔论文中出现的频率曲线数值表，以检验罗纳德·费希尔得出的精确分布与先前已知近似分布是否一致。到1916年5月，他们仍以友好的方式通信。然而，皮尔逊误解了罗纳德·费希尔最大似然法的假设，并在1917年5月与他的工作人员合著的那篇关于频率曲线制表的Cooperative Study论文中不公正地批评了该方法。罗纳德·费希尔认为皮尔逊的批评没有根据，便以一篇论文作为回应，该论文批评了Cooperative Study中的例子，甚至到了嘲笑它们的地步。罗纳德·费希尔重新审视了他早先与皮尔逊的通信，注意到自己的许多论文曾被拒绝，于是得出结论：皮尔逊对此负有责任。

尽管两人都是统计方法的坚定倡导者，他们的方法却相当不同。皮尔逊使用他测量的大样本，然后试图推断数据中的相关性。另一方面，罗纳德·费希尔追随戈塞特，试图使用小样本，并且不是推断相关性，而是寻找原因。这场争论变得如此严重，以至于罗纳德·费希尔在1919年拒绝了弗朗西斯·高尔顿实验室首席统计师的职位，因为那将意味着在皮尔逊手下工作。争论继续加剧，双方都抓住每一个机会攻击对方的观点。

皮尔逊的妻子于1928年去世，次年他与系里的同事Margaret Victoria Child再婚。皮尔逊于1933年夏天辞去弗朗西斯·高尔顿讲席，大学学院决定将他的系一分为二。他的儿子伊根·皮尔逊成为统计系主任，而罗纳德·费希尔被任命为弗朗西斯·高尔顿讲席，接替皮尔逊担任优生学系主任。

格林伍德在[9]中这样描述皮尔逊的性格：-

皮尔逊是他那个时代最有影响力的大学教师之一；他费尽心思使自己的讲解清晰易懂，能够吸引大批听众，无论是学生还是对他所讲主题没有特别兴趣的偶然听众。在他较小的研究学生圈子里，他激发了热烈的个人爱戴；没有哪位系主任比他更慷慨地回报忠诚的服务。……他具有其优点所伴随的一些缺点；他专横，……他强烈而真诚地信仰思想自由，但往往把智力上的意见分歧归因于愚蠢甚至道德上的偏差。他与学生之间的个人关系有时会痛苦地中断多年；但令人欣慰的是，这些破裂的友谊最终大多都愉快地恢复了。只有智力上的分歧才会扰乱和谐；在普通的社会生活关系中，他是一位迷人的主人、客人或旅伴。皮尔逊对那些仅通过著作了解他的人也有很大影响。许多人对他与其说是爱戴，不如说是钦佩和畏惧；他在一些人心中激起了强烈的敌意。

沃克在[26]中这样总结皮尔逊的重要性：-

皮尔逊对统计技术做出了如今看来具有持久重要性的贡献，但这些技术的重要性不如他所做的另一件事：他将科学界从仅仅对统计研究感兴趣的状态，激发为众多训练有素的人热切努力的状态，这些人发展新理论，从各个领域收集和分析统计数据，计算新表，并重新审视统计哲学的基础。这是一项规模惊人的成就。他的实验室是一个世界中心，来自各国的人在此学习。在全部科学史中，很少有人像他那样激励了如此多的人去耕耘和拓展他们自己播下的领域。他为科学家提供了统摄一切科学的一般方法论概念，这是对现代思想的伟大贡献之一。

我们在上文提到了皮尔逊获得的一些荣誉。我们还要指出，他获得了圣安德鲁斯大学和伦敦大学的荣誉学位。他还被选为爱丁堡皇家学会的会士。

Karl Pearson's mother Fanny Smith and his father William Pearson were both from Yorkshire families. William was a barrister of the Inner Temple [26]:-

He was a man of great ability, with exceptional mental and physical energy and a keen interest in historical research, traits which his son also exhibited.

William and Fanny named their second child Carl and he used this name until he was about 23 years old when he changed the spelling to Karl. In this article we shall refer to him either as Karl or as Pearson.

Karl, together with his one older brother and one younger sister, were brought up in an upper-middle class family. After being educated at home up to the age of nine years, he was sent to University College School, London. He studied there until he was sixteen, but he was then forced to leave due to illness. A private tutor was engaged to teach him at home and he took the Cambridge Scholarship Examinations in 1875 and, coming second in the examinations, he won a scholarship to King's College.

At Cambridge he was taught by Stokes, Maxwell, Cayley and Burnside. His coach was perhaps the most famous of all the Cambridge coaches, namely Routh. He spoke of his undergraduate years saying (see [3]):-

At Cambridge I studied mathematics under Routh, Stokes, Cayley, and Clerk Maxwell, but read papers on Spinoza.

But these were days of great happiness for Pearson [22]:-

There was pleasure in the friendships, there was pleasure in the fights, there was pleasure in the coaches' teaching, there was pleasure in searching for new lights as well in mathematics as in philosophy and religion.

As he indicates in these quotations, his studies at Cambridge were unusually broad. He read Goethe, Dante, and Rousseau, read about the history of religious thought, and enjoyed debating with students of moral philosophy about their subject.

Pearson was never one to accept authority and this comes out clearly during his undergraduate years at Cambridge. At that time divinity lectures and attendance at chapel were compulsory. Pearson was deeply interested in religion yet hated the compulsory nature of these activities. He argued successfully to have the University regulations changed so that attendance was no longer compulsory at divinity lectures and, having won this battle, fought the second battle on compulsory chapel with his father's help. Having won, he surprised the University authorities by continuing to attend chapel but, of course, to Pearson there was a world of difference between attending voluntarily and compulsory attendance.

He graduated from Cambridge University in 1879 as Third Wrangler in the Mathematical Tripos (meaning that he was ranked third among those who gained a First Class degree). He then travelled to Germany to study at the University of Heidelberg. There he studied physics under G H Quincke and metaphysics under Kuno Fischer. He next visited the University of Berlin, where he attended the lectures of the famous physiologist Émile du Bois-Reymond on Darwinism (Émile was a brother of Paul du Bois-Reymond, the mathematician). Other subjects which he studied in Berlin included Roman Law, taught by Bruns and Mommsen, medieval and 16th century German Literature, and Socialism. He was strongly influenced by the courses he attended at this time and he became sufficiently expert on German literature that he was offered a post in the German Department of Cambridge University. On his return to England in 1880, Pearson first went to Cambridge [3]:-

Back in Cambridge, I worked in the engineering shops, but drew up the schedule in Mittel- and Althochdeutsch for the Medieval Languages Tripos.

His first book, The New Werther, was published at this time. In it Pearson gives a clear indication of why he studied so many diverse subjects (see for example [17] or [26] or The New Werther):-

I rush from science to philosophy, and from philosophy to our old friends the poets; and then, over-wearied by too much idealism, I fancy I become practical in returning to science. Have you ever attempted to conceive all there is in the world worth knowing - that not one subject in the universe is unworthy of study? The giants of literature, the mysteries of many-dimensional space, the attempts of Boltzmann and Crookes to penetrate Nature's very laboratory, the Kantian theory of the universe, and the latest discoveries in embryology, with their wonderful tales of the development of life - what an immensity beyond our grasp! ... Mankind seems on the verge of a new and glorious discovery. What Newton did to simplify the planetary motions must now be done to unite in one whole the various isolated theories of mathematical physics.

Despite the feelings he expresses in this quote, Pearson decided to study law so that he might, like his father, be called to the Bar. Again quoting Pearson's own account [3]:-

Coming to London, I read in chambers in Lincoln's Inn, drew up bills of sale, and was called to the Bar, but varied legal studies by lecturing on heat at Barnes, on Martin Luther at Hampstead, and on Lasalle and Marx on Sundays at revolutionary clubs around Soho.

Despite being called to the Bar in 1882, Pearson never practised law. During 1882-84 he lectured around London on a wide variety of topics such as German social life, the influence of Martin Luther, and historical topics. He also wrote essays, articles and reviews as well as substituting for professors of mathematics at King's College and University College London.

He spent most of his career at University College, London, after he was appointed to the Chair of Applied Mathematics in 1885 as Goldsmid Professor. One of his former pupils writes in [3]:-

He was no "textbook" teacher, and could instil an understanding of the fundamentals of a subject with greater ease and in a shorter time than any mathematical lecturer I have since known. His personal appearance was arresting: the typical Greek athlete, with finely cut features and a magnificent physique. ... He was a pertinacious controversialist, but in any personal discussion his humorous twinkle was disarming.

From 1884 to 1890 Pearson was highly productive. As well as giving lectures on statics, dynamics and mechanics, he completed the unfinished first volume of Clifford's The Common Sense of the Exact Sciences (published in 1885), completed and edited the half written first volume of Todhunter's History of the Theory of Elasticity, began working on the second volume which had hardly been started by Todhunter, and published many papers on applied mathematics. He also lectured on The Ethic of Free Thought, and undertook research on a number of historical topics such as the evolution of Western Christianity. In 1885 he was a founder member of the Men and Women Club dedicated to discussion of the role of men and women in society, and at meetings of the club he met Maria Sharpe. Their marriage in 1890 produced three children; Egon Pearson (born 1895) who followed his father's profession, and two daughters Sigrid Loetitia who was three years older than Egon and Helga Sharpe who was three years younger.

It is worth pausing to realise that Pearson is known as one of the founders of statistics, yet we have reached 1890 and the 33 year old professor of applied mathematics, although having a high reputation in a wide variety of areas, had still not begun to work on statistical problems. As Aldrich writes in [6]:-

... his contribution to statistical methodology overshadowed his contribution to any substantive field. His statistical contributions can be divided into ways of arranging numerical facts - univariate and multivariate - estimation and testing.

Two events changed the course of his career. The first was the publication by Galton of his book Natural Inheritance in 1889. The second was the appointment of Weldon as Professor of Zoology at University College London in 1890. Walker writes in [26]:-

The importance for science of the intense personal friendship which soon sprang up between Pearson and Weldon, then both in their early thirties, can scarcely be exaggerated. Weldon asked the questions that drove Pearson to some of his most significant contributions.

Through Weldon and Galton's book, Pearson became interested in developing mathematical methods for studying the processes of heredity and evolution. From 1893 to 1912 he wrote 18 papers entitled Mathematical Contributions to the Theory of Evolution which contain his most valuable work. These papers contain contributions to regression analysis, the correlation coefficient and includes the chi-square test of statistical significance (1900). His chi-square test was produced in an attempt to remove the normal distribution from its central position.

His book The Grammar of Science (1892) was remarkable in that it anticipated some of the ideas of relativity theory. It was wide ranging and attempted to extend the influence of science into all aspects. Pearson coined the term 'standard deviation' in 1893. His work was influenced by the work of Edgeworth while he in turn influenced the work of Yule.

Pearson was a co-founder, with Weldon and Galton, of the statistical journal Biometrika . This came about because he had presented a paper to the Royal Society, of which he had been elected a Fellow in 1896 and received its Darwin Medal in 1898, in 1900. The paper looked at heredity and argued using a mathematical analysis of large amounts of collected data. Biologists in the Royal Society were not, however, prepared to accept biological conclusions based on mathematical analysis. Weldon, in a letter to Pearson on 16 November 1900, suggested solving the problem of getting such papers published by setting up their own journal. Pearson was enthusiastic and suggested they name the journal Biometrika . The first volume appear in October 1901 with Pearson as its editor, a role he continued to hold until his death 35 years later.

From around 1906 Pearson put a large effort into setting up a postgraduate centre. He did this (see [17]):-

... to make statistics a branch of applied mathematics with a technique and nomenclature of its own, to train statisticians as men of science ... and in general to convert statistics in this country from being the playing field of dilettanti and controversialists into a serious branch of science, which no man could attempt to use effectively without adequate training, and more than he could attempt to use the differential calculus, being ignorant of mathematics.

He was the first Galton Professor of Eugenics, holding the chair from 1911 to 1933. Galton had set up the Eugenics Record Office in 1904 and in 1906 he put Pearson in charge. Pearson already ran the Biometric Laboratory and in 1911 the two laboratories were combined into the Department of Applied Statistics in University College. Galton had expressed the wish that Pearson should be offered the chair, so becoming head of the new Department. In so doing Pearson gave up his Goldsmid chair.

Pearson had a long, bitter, and very public dispute with Fisher. At first they exchanged friendly letters after Pearson received a manuscript from Fisher in September 1914 of a paper he was submitting for publication. Pearson's initial response was to say (see [18]):-

I congratulate you very heartily on getting out the actual distribution form ... if the analysis is correct which seems highly probable, I should be delighted to publish the paper in Biometrika.

Again a week later [18]:-

I have now read your paper fully and think it marks a distinct advance.

Pearson then offered to have his staff at the Galton Laboratories work on a tabulation of values for the frequency curves arising in Fisher's paper to test the exact distribution produced by Fisher against previously known approximations. By May 1916 they were still corresponding in a friendly manner. However Pearson misunderstood the assumptions of Fisher's maximum likelihood method, and criticised it unfairly in the May 1917 Cooperative Study paper which he co-authored with his staff concerning tabulating the frequency curves. Fisher, believing that Pearson's criticism was unwarranted, responded with a paper which criticised examples in the Cooperative Study to the extent of ridiculing them. Fisher had looked again at his earlier correspondence with Pearson, noticed that many of his papers had been rejected, and concluded that Pearson had been responsible.

Although both were strong advocates of statistical methods their approach was rather different. Pearson used large samples which he measured and the tried to deduce correlations in the data. Fisher, on the other hand, followed Gosset in trying to use small samples and, rather than deduce correlations, to find causes. The dispute became bad enough to have Fisher turn down the post of Chief Statistician at the Galton Laboratory in 1919 since it would have meant working under Pearson. The dispute continued to grow in intensity with each taking every opportunity to attack the other's views.

Maria, Pearson's wife, died in 1928 and he remarried Margaret Victoria Child, a co-worker in his department, in the following year. Pearson resigned from the Galton Chair in the summer of 1933 and University College decided to split his Department into two. His son Egon Pearson became head of the Department of Statistics, while Fisher was appointed to the Galton Chair to succeed Pearson as head of the Department of Eugenics.

Greenwood writes of Pearson's character in [9]:-

Pearson was among the most influential university teachers of his time; he took great pains to be intelligible and could hold a large audience either of students or merely casual hearers who were without special interest in his topics. In the smaller circle of his research pupils he inspired enthusiastic personal affection; no head of a department repaid loyal service more generously. ... He had some of the defects of his qualities; he was dominating, ... he had an intense and genuine belief in freedom of thought but was apt to attribute intellectual differences of opinion to stupidity or even moral obliquity. Personal relations between him and his pupils were sometimes painfully interrupted for years; but it is pleasant to record that eventually most of these broken friendships were happily resumed. Only intellectual differences disturbed harmony; in the ordinary social relations of life he was a charming host, guest, or travelling companion. Pearson's influence upon those who only knew him through his writings was also great. He was admired and feared, rather than loved, by many; in some he aroused bitter hostility.

Walker sums up Pearson's importance in [26] as follows:-

Although Pearson made contributions to statistical technique that now appear to be of enduring importance, these techniques are of less importance than what he did in arousing the scientific world from a state of sheer interest in statistical studies to one of eager effort by a large number of well-trained persons, who developed new theory, gathered and analysed statistical data from every field, computed new tables, and re-examined the foundations of statistical philosophy. This is an achievement of fantastic proportions. His laboratory was a world centre in which men from all countries studied. Few men in all the history of science have stimulated as many other people to cultivate and to enlarge the fields they themselves had planted. he provided scientists with the concept of a general methodology underlying all science, one of the great contributions to modern thought.

We have mentioned above some of the honours which Pearson received. Let us also note that he received an honorary degree from the University of St Andrews and from the University of London. He was also elected a fellow of the Royal Society of Edinburgh.