The development of geology during the first half of the nineteenth century is now considered to be more complicated than was once thought. The positivistic picture of two conflicting schools, one of them allegedly modern and progressive, the other supposedly conservative and scriptural, is too simplistic and misleading. First, the influence of the Bible has been exaggerated. It is true that in the seventeenth and eighteenth centuries the Flood had been given an important role as a geological agent, but in the early nineteenth century there were hardly any professional geologists who defended this view. At least, it is not correct to associate either neptunism, catastrophism, or diluvialism with the Mosaic tradition. Secondly, the use of such terms as ‘catastrophism’ and ‘diluvialism’ has been unfortunate in so far as they have led to biblical associations; these terms must be given a more precise meaning. Thirdly, in the evaluation of the geology of the period, not enough weight has been given to the historical context. From our knowledge of modern geology alone it is not possible to judge what was loose speculation or empirical science at that time. Lyell's contributions to geology, as well as those of his opponents, should be considered and examined in more detail.

This is a theoretical paper. A little theory goes a long way in history, for me; but it is good to collect as much as is feasible in one paper, so that gaps and inconsistencies can be noticed. I use ‘theory’ in the definite sense of a set of hypothetical statements such that deductions can be made and compared with data, facts, or generalizations obtained in some other way than as derivation from theory. Deductions need not always be rigorous, and there may be two or more ‘solutions’ obtainable, of which the scientist may choose one and discard the rest (for example, he may discard all ‘imaginary’ solutions). I am ignoring the differences between propositions, demonstrations, problems, and the like. Actually there must always be several statements, including rules of procedure, in the set; but often many are assumed and only the new or controversial one is stated as ‘the’ hypothesis of Mr X.

The Geological discoveries made during the early nineteenth century resulted in a series of general, predominantly didactic studies, the chief purpose of which was the compilation of large amounts of data. Many of these books were quickly translated from one language into another, and the work of Sir Charles Lyell was, naturally enough, no exception.

History is the science which investigates the successive changes that have taken place in the material and intellectual conditions of man; it inquires into the causes of those changes, and the influence which they have exerted in modifying the life and mind of mankind.

Two of the most influential evaluations of Charles Lyell's geological ideas were those of the philosophers of science, John F. W. Herschel and William Whewell. In this paper I shall argue that the great difference between these evaluations—whereas Herschel was fundamentally sympathetic to Lyell's geologizing, Whewell was fundamentally opposed—is a function of the fact that Herschel was an empiricist and Whewell a rationalist. For convenience, I shall structure the discussion around the three key elements in Lyell's approach to geology. First, he was an actualist: he wanted to explain past geological phenomena in terms of causes of the kind that are operating at present. Second, he was a uniformitarian: he wanted to explain only in terms of causes of the degree operating at present; that is, he wanted to avoid ‘catastrophes’. Third, as a geologist he saw the earth as being in a steady-state, in which all periods are essentially similar to one another. Because they will prove important, I draw attention also to two major features of Lyell's programme. First, there is his theory of climate, which suggests, ‘without help from a comet’, that earthly temperature fluctuations are primarily a function of the constantly changing distribution of land and sea. Clearly this theory is actualistic, for it is based on such present phenomena as the Gulf Stream; it is also uniformitarian and supports a steady-state world picture. Second, there is Lyell's denial that the fossil record is progressive, his criticism of Lamarckian evolutionism, ostensibly on the grounds that modern evidence is against it (i.e. it fails actualistically), and his rather veiled claim that the origins of species will nevertheless prove in some way natural, that is, subject to causes falling beneath lawlike regularities in principle discernible by us.

In offering a contribution to a session concerned with ‘the background to Lyell's work’, I want to begin by launching a caveat against the notion of ‘background’. If, in the case of Lyell, ‘background’ features remained in obscurity then they can be dismissed; if, however, ‘background’ features were important then they become foreground. This point is not merely linguistic pedantry, because if we look at the scientific institutions of London in the period 1820–41, it is too easy to assume, with naïve optimism, that if they existed they must have been functionally effective for scientists. This was not necessarily so. We have to discover, as a matter of contingent reality, the ways in which particular institutions actually affected the careers of individual scientists. In this paper, therefore, I shall offer some general observations on London scientific institutions; and then I shall analyse Lyell's varying allegiances to them in terms of his ambitions concerning the shape and direction of his career.

During the decades following the publication of Darwin's Origin of species in 1859, religious belief in England and in particular the Church of England experienced some of the most intense criticism in its history. The early 1860s saw the appearance of Lyell's Evidence of the antiquity of man (1863), Tylor's research on the early history of mankind (1863), Renan's Vie de Jésus (1863), Pius IX's encyclical, Quanta cura, and the accompanying Syllabus errarum, John Henry Newman's Apologia (1864), and Swinburne's notorious Atalanta in Calydon (1865); it was in this period also that Arthur Stanley was appointed Dean of Westminster, and that Bills were introduced in Parliament to amend or repeal the ‘Test Acts’ as they affected universities. They were the years that witnessed Lyell present the case for geology at the British Association at Bath (1864), the first meeting of the X-Club (1864), and the award of the Royal Society's Copley Medal to Charles Darwin. These were the years in which, as Owen Chadwick has put it, ‘the controversy between “science” and “religion” took fire’.

The concepts of action and reaction before Newton have received so little attention from historians that the unwary student might easily get the impression that Newton was the first to concern himself seriously with the problem. In fact, the subject had a long prehistory extending back to Aristotle and it was actively discussed by physicists during the half-century preceding the publication of Principia mathematica in 1687. Although there is no evidence that Newton himself was much influenced by the views of others on the subject, they formed a part of the intellectual background of the Principia which should not be ignored.