Experience, so important to Oliver Wendell Holmes in the realm of the law, would prove no less invaluable to his colleague from the Saturday Club, the philosopher and psychologist William James. Despite his impeccably Welsh name, James was in fact of Irish stock.33
The first William James, the philosopher’s grandfather, was a dry goods millionaire who, but for John Jacob Astor, would have been the richest man in New York state.34 His son Henry liked the bottle too much and was disinherited on William’s death, but contested the will, and won. According to Richard Hofstadter, William James was the first great beneficiary of the scientific education then emerging in the United States during the 1860s and 1870s (and considered later in this chapter). A wag suggested that he was a better writer than his brother Henry, who was a better psychologist. Like Wendell Holmes, William James was sceptical of certitude. One of his favourite phrases was ‘Damn the Absolute!’35 Instead of a formal education, he had travelled across Europe with his family, and although he had never stayed long at any particular school, this travelling gave him experience. (Somewhere he picked up the ability to draw, too.36) He did finally settle on a career, in science, at Harvard in 1861 and formed part of the circle around Louis Agassiz, the discoverer of the Ice Age and at the time one of the most vociferous critics of Charles Darwin, who based his opposition, he insisted, on science.37 After his early successes, Agassiz’ fortunes had taken a turn for the worse when he lost a quantity of money on a publishing venture. The offer of a lecture series in America promised a way out and indeed, in Boston he was a great success (the Saturday Club was often referred to as Agassiz’ Club). At the time he was in Boston, Harvard was in the process of setting up its school of science (see below, this chapter), and a special chair was founded for him.38
It was Agassiz’ battle with Darwin that interested James the most and, says one of his biographers, it was the example of the Swiss that decided him to become a scientist.39 Agassiz, a deist, described Darwin’s theory as ‘a mistake’; he disputed its facts and considered it ‘mischievous’ rather than serious science.40 James wasn’t so sure. He was particularly sceptical of Agassiz’ dogmatism whereas he thought evolutionary theory sparked all sorts of fresh ideas and, what he liked most, revealed biology as acting on very practical, even pragmatic, principles. Natural selection, for James, was a beautiful idea because it was so simple and down-to-earth, with adaptation being no more than a way to address practical problems wherever they occurred.41 Life, James liked to say, is to be judged by consequences.42
In 1867, after his spell at Harvard, James went to Germany. In the nineteenth century some nine thousand Americans visited Germany to study in the universities there, which, as we have seen, were organised along the lines of the various disciplines, rather than as places to teach priests, doctors and lawyers. James went to study with the leading experimental psychologist of the day, Wilhelm Wundt, who had set up the first psychological laboratory, at Leipzig. Wundt’s speciality – physiological psychology, or ‘psychophysics’ – was then regarded as the most likely area to produce advances. The basic assumption of physiological psychology was that all mind (conscious) processes are linked with brain processes, that every conscious thought or action has an organic, physical basis. One of the effects of this was that experimentation had replaced introspection as the primary means of investigation. In this so-called New Psychology, feelings and thoughts were understood as the result of ‘brain secretions’, organic changes which would in time yield to experimental manipulation. James was disappointed by the New Psychology, and by Wundt, who is little read now (and in fact it has now emerged that Wundt himself was drifting away from a rigid experimental approach to psychology).43 Wundt’s chief legacy is that he improved the standing of psychology thanks to his experimental approach. This improved standing of psychology rubbed off on James.
If Wundt’s influence turned out to be incidental, that of the Peirces was much more consequential. Like the Wendell Holmeses and the Jameses, the Peirces were a formidable father-and-son team. Benjamin Peirce may well have been the first world-class mathematician the United States produced (the Irish mathematician William Rowan Hamilton thought that Peirce was ‘the most massive intellect with which I have ever come into close contact’) and he too was one of the eleven founding members of the Saturday Club.44
His son Charles was equally impressive. A prodigy who wrote a history of chemistry when he was eleven and had his own laboratory at twelve, he could write with both hands at the same time. No wonder, perhaps, that he was bored at Harvard, drank too much, and graduated seventy-ninth in his class of ninety.45 That was the low point. Later, he built on his father’s work and, between them, they conceived the philosophy of pragmatism, which was grounded in mathematics. ‘It is not easy to define pragmatism: the Italian Papini observed that pragmatism was less a philosophy than a method of doing without one.’46 In the first place, Benjamin Peirce became fascinated by the theories and calculations of Pierre-Simon Laplace and Karl Friedrich Gauss (covered in Chapter 32), in particular their ideas about probability.47 Probability, or the laws of error, had a profound impact on the nineteenth century because of the apparent paradox that the accidental fluctuations that make phenomena deviate from their ‘normal’ laws, are themselves bound by a (statistical) law. The fact that this law applied even to human beings pointed many towards determinism.48
Charles Peirce was not one of them. He believed that he could see spontaneous life around him at every turn. (And he attacked Laplace in print.) He argued that, by definition, the laws of nature themselves must have evolved.49 He was Darwinian enough to believe in contingency, indeterminacy, and his ultimate philosophy was designed to steer a way through the confusion.50 In 1812, in his Théorie analytique des probabilités, Laplace had said ‘We must . . . imagine the present state of the universe as the effect of its prior state and as the cause of the state that will follow.’ This is Newton’s billiard-ball theory of matter, applied generally, even to human beings, and where chance has no part.51 Against this, in his Theory of Heat, published in 1871, the Scottish physicist James Clerk Maxwell had argued that the behaviour of molecules in a gas could be understood probabilistically. (Peirce met Maxwell on a visit to Cambridge in 1875.)52 The temperature of a gas in a sealed container is a function of the velocity of the molecules – the faster they move, the more they collide and the higher the temperature. But, and most importantly from a theoretical point of view, the temperature is related to the average velocity of the molecules, which vary in their individual speeds. How was this average to be arrived at, how was it to be understood? Maxwell argued that ‘the velocities are distributed among the particles according to the same law as the errors are distributed among the observations in the theory of the “method of least squares”’. (This had first been observed among astronomers: see here.)53 Maxwell’s point, the deep significance of his arguments, for the nineteenth century, was that physical laws are not Newtonian, not absolutely precise. Peirce grasped the significance of this in the biological, Darwinian realm. In effect, it created the circumstances where natural selection could operate. Menand asks us to consider birds as an example. In any particular species, of finch say, most individuals will have beaks within the ‘normal distribution’, but every so often, a bird with a beak outside the range will be born, and if this confers an evolutionary advantage it will be ‘selected’. To this extent, evolution proceeds by chance, not on an entirely random basis but according to statistical laws.54