路德维希·玻尔兹曼Ludwig Boltzmann

路德维希·玻尔兹曼 的父亲是一名税务官员。玻尔兹曼 于 1866 年获得维也纳大学博士学位，学位论文是关于气体动理论的，由 约瑟夫·斯特凡 指导。获得博士学位后，他成为其老师 约瑟夫·斯特凡 的助手。

玻尔兹曼 曾在格拉茨任教，后转到海德堡，再到柏林。在这些地方，他师从 Bunsen、古斯塔夫·基尔霍夫 和 赫尔曼·冯·亥姆霍兹。

1869 年，玻尔兹曼 被任命为格拉茨的理论物理讲席。他担任此职四年，然后于 1873 年接受了维也纳的数学讲席。他在任何地方都没有待很久，三年后他又回到格拉茨，这次担任实验物理讲席。

玻尔兹曼至少半开玩笑地说过，他之所以频繁搬迁，是因为他出生在狂欢节舞会即将结束的时刻。这半是玩笑，因为他确实感到自己的天性使他容易在快乐与悲伤之间快速摇摆。他的个性无疑对他的职业方向产生了重大影响，而人际关系中他总是非常心软，这一点也起了很大作用。他饱受抑郁情绪与高涨、 expansive 或易怒情绪交替的困扰。的确，他矮胖、卷发的外表似乎与他的个性相符。他的未婚妻称他为她的“甜蜜胖宝贝”。

又过了三年，在1894年，玻尔兹曼搬回了维也纳，这次是接任因他的老师约瑟夫·斯特凡去世而空出的理论物理学讲席。然而，次年恩斯特·马赫被任命为维也纳的科学史与科学哲学讲席。玻尔兹曼有许多科学上的对手，但对玻尔兹曼来说，马赫不仅仅是科学上的对手，因为两人个人关系不佳。

1900年，由于不喜欢与马赫共事，玻尔兹曼搬到了莱比锡，但在这里他成了他最强大的科学对手威廉·奥斯特瓦尔德的同事。尽管科学上存在分歧，玻尔兹曼和奥斯特瓦尔德个人关系良好。尽管如此，由于下文描述的与奥斯特瓦尔德的科学争论而抑郁，玻尔兹曼在莱比锡期间曾试图自杀，但未成功。

1901年，马赫因健康不佳从维也纳退休，因此玻尔兹曼离开维也纳的理由消失了。1902年，他回到维也纳，重新担任在此期间一直空缺的理论物理学讲席。除了教授数学物理学外，玻尔兹曼还被安排教授马赫的哲学课程。他的哲学讲座迅速成名，听众很快多到最大的演讲厅都容纳不下。事实上，由于这些讲座的名声，玻尔兹曼被邀请到弗朗茨·约瑟夫的宫殿。

玻尔兹曼的声名建立在他发明统计力学的基础上。这是他独立于约西亚·威拉德·吉布斯完成的。他们的理论将原子和分子的性质与行为同它们作为构成单元的物质的大尺度性质与行为联系了起来。

玻尔兹曼在1871年得到了詹姆斯·克拉克·麦克斯韦-玻尔兹曼分布，即分子运动的平均能量在每个方向上相同。他是最早认识到詹姆斯·克拉克·麦克斯韦电磁理论重要性的人之一。

1884年，玻尔兹曼发展了约瑟夫·斯特凡的工作，他表明1879年提出的约瑟夫·斯特凡关于黑体辐射的经验$T^{4}$定律如何能从热力学原理推导出来。

玻尔兹曼用probability研究统计力学，描述原子的性质如何决定物质的性质。特别是他的工作涉及热力学第二定律，他在1890年代从力学原理推导出了这一定律。

牛顿力学的方程在时间上可逆，儒勒·昂利·庞加莱证明了如果一个力学系统处于给定状态，它将无限频繁地返回到任意接近给定状态的状态。恩斯特·策梅洛推断出热力学第二定律在力学系统中是不可能的。玻尔兹曼断言熵几乎总是增加，而不是总是增加。然而他相信儒勒·昂利·庞加莱的结果虽然在理论上是正确的，但在实践中无法观察到，因为系统返回到接近其原始状态之前的时间太长。

玻尔兹曼的思想未被许多科学家接受。1895年，在吕贝克的一次科学会议上，Wilhelm Ostwald提交了一篇论文，他在文中指出：-

自然现象的实际不可逆性由此证明了存在无法用力学方程描述的过程，科学唯物主义的判决就此定案。

阿诺·索末菲，当时也在会上，描述了由此引发的奥斯特瓦尔德与玻尔兹曼之间的论战。阿诺·索末菲写道：-

……玻尔兹曼得到了菲利克斯·克莱因的支持。玻尔兹曼与奥斯特瓦尔德之间的论战，就像公牛与灵巧斗士的搏斗。然而这一次，公牛获胜了……玻尔兹曼的论点占了上风。我们这些当时的年轻数学家，全都站在玻尔兹曼一边……

奥斯特瓦尔德带头反对玻尔兹曼的想法，这些想法遭到许多欧洲科学家的反对，他们误解了这些想法，没有完全把握其推理的统计性质。然而，包括马赫在内的一些人认为，这些论战过于激烈，而当玻尔兹曼在作为奥斯特瓦尔德同事期间试图自杀时，情况看来确实如此。

1904年，玻尔兹曼参观了美国圣路易斯的世界博览会。他就应用数学作了演讲，然后继续访问了乔治·伯克利和斯坦福。不幸的是，他没有意识到在这次访问中了解到的关于辐射的新发现即将证明他的理论是正确的。

玻尔兹曼继续捍卫他对原子结构的信念，并在1905年的一篇出版物Populäre SchriftenⓉ（通俗写作）中，试图解释物理世界如何能用微分方程来描述，后者代表了宏观视角，却没有代表底层的原子结构。-

请允许我老生常谈地说一句：对于那些认为通过考虑微分方程就能摆脱原子论的人来说，森林遮住了树木。

对他的工作的攻击仍在继续，他开始觉得，尽管他捍卫了自己的理论，他毕生的工作仍即将崩溃。玻尔兹曼抑郁且健康状况不佳，就在实验证实他的工作之前自杀了。

他与妻子和女儿在的里雅斯特附近的杜伊诺湾度假时，趁妻女游泳之际自缢身亡。然而，他的自杀原因可能被错误地归咎于其思想未获接受。我们永远不会知道真正的原因，那可能是导致他抑郁的精神疾病所致。

Ludwig Boltzmann's father was a taxation official. Boltzmann was awarded a doctorate from the University of Vienna in 1866 for a thesis on the kinetic theory of gases supervised by Josef Stefan. After obtaining his doctorate, he became an assistant to his teacher Josef Stefan.

Boltzmann taught at Graz, moved to Heidelberg and then to Berlin. In these places he studied under Bunsen, Kirchhoff and Helmholtz.

In 1869 Boltzmann was appointed to a chair of theoretical physics at Graz. He held this post for four years then, in 1873, he accepted the chair of mathematics at Vienna. He did not stay very long in any place and after three years he was back in Graz, this time in the chair of experimental physics.

Boltzmann, at least half jokingly, used to say that the reason he moved around so much was that he was born during the dying hours of a Mardi Gras ball. It was only half joking since he did feel that his nature made him subject to rapid swings between happiness and sadness. His personality certainly had a major impact on the direction that his career took and personal relationships, where he was always very soft-hearted, played a big part. He suffered from an alternation of depressed moods with elevated, expansive or irritable moods. Indeed his physical appearance, being short and stout with curly hair, seemed to fit his personality. His fiancée called him her "sweet fat darling".

After another three years, in 1894, Boltzmann moved back to Vienna, this time to the chair of theoretical physics which became vacant on the death of his teacher Josef Stefan. However, the following year Ernst Mach was appointed to the chair of history and philosophy of science at Vienna. Boltzmann had many scientific opponents but, to Boltzmann, Mach was more than a scientific opponent as the two were on bad personal terms.

In 1900, because of his dislike of working with Mach, Boltzmann moved to Leipzig but here he became a colleague of his strongest scientific opponent Wilhelm Ostwald. Despite their scientific differences Boltzmann and Ostwald were on good personal terms. Despite this, depressed by scientific arguments with Ostwald which are described below Boltzmann unsuccessfully attempted suicide during his time in Leipzig.

In 1901 Mach retired from Vienna due to ill health, and because of this Boltzmann's reason for moving from Vienna had gone. In 1902 he returned to Vienna to his chair of theoretical physics which had not been filled in the intervening period. In addition to his teaching in mathematical physics, Boltzmann was given Mach's philosophy course to teach. His philosophy lectures quickly became famous with the audience soon being too large for the biggest lecture hall available. In fact because of the fame of these lectures Boltzmann was invited to the Palace of Franz Josef.

Boltzmann's fame is based on his invention of statistical mechanics. This he did independently of Willard Gibbs. Their theories connected the properties and behaviour of atoms and molecules with the large scale properties and behaviour of the substances of which they were the building blocks.

Boltzmann obtained the Maxwell-Boltzmann distribution in 1871, namely the average energy of motion of a molecule is the same for each direction. He was one of the first to recognise the importance of Maxwell's electromagnetic theory.

In 1884 the work of Josef Stefan was developed by Boltzmann who showed how Josef Stefan's empirical $T^{4}$ law for black body radiation, formulated in 1879, could be derived from the principles of thermodynamics.

Boltzmann worked on statistical mechanics using probability to describe how the properties of atoms determine the properties of matter. In particular his work relates to the Second Law of Thermodynamics which he derived from the principles of mechanics in the 1890s.

The equations of Newtonian mechanics are reversible in time and Poincaré proved that if a mechanical system is in a given state it will return infinitely often to a state arbitrarily close to the given one. Zermelo deduced that the Second Law of Thermodynamics is impossible in a mechanical system. Boltzmann asserted that entropy increases almost always, rather than always. However he believed that Poincaré's result, although correct in theory, was in practice impossible to observe since the time before a system returns to near its original state was too long.

Boltzmann's ideas were not accepted by many scientists. In 1895, at a scientific meeting in Lübeck, Wilhelm Ostwald presented a paper in which he stated:-

The actual irreversibility of natural phenomena thus proves the existence of processes that cannot be described by mechanical equations, and with this the verdict on scientific materialism is settled.

Sommerfeld, who was at the meeting, described the resulting battle between Ostwald and Boltzmann. Sommerfeld wrote:-

... Boltzmann was seconded by Felix Klein. The battle between Boltzmann and Ostwald resembled the battle of the bull with the supple fighter. However, this time the bull was victorious ... . The arguments of Boltzmann carried the day. We, the young mathematicians of that time, were all on the side of Boltzmann ... .

Ostwald led the opposition to Boltzmann's ideas which were opposed by many European scientists, they misunderstood them, not fully grasping the statistical nature of his reasoning. However some, including Mach, thought the arguments were too violent, and this certainly appeared to be the case when Boltzmann attempted suicide while a colleague of Ostwald.

In 1904 Boltzmann visited the World's Fair in St Louis, USA. He lectured on applied mathematics and then went on to visit Berkeley and Stanford. Unfortunately he failed to realise that the new discoveries concerning radiation that he learnt about on this visit were about to prove his theories correct.

Boltzmann continued to defend his belief in atomic structure and in a 1905 publication Populäre Schriften Ⓣ he tried to explain how the physical world could be described by differential equations which represented the macroscopic view without representing the underlying atomic structure. :-

May I be excused for saying with banality that the forest hides the trees for those who think that they disengage themselves from atomistics by the consideration of differential equations.

Attacks on his work continued and he began to feel that his life's work was about to collapse despite his defence of his theories. Depressed and in bad health, Boltzmann committed suicide just before experiment verified his work.

On holiday with his wife and daughter at the Bay of Duino near Trieste, he hanged himself while his wife and daughter were swimming. However the cause of his suicide may have been wrongly attributed to the lack of acceptance of his ideas. We will never know the real cause which may have been the result of mental illness causing his depression.