Published online by Cambridge University Press: 28 February 2022
Any discussion of probability theory in early nineteenth-century Britain requires a specially vigorous exercise of the historical imagination. A century of subsequent thought about the foundations of the subject has made both historians and philosophers of science only too aware of how elusive and polyvalent a term ‘probability’ is; indeed, since Carnap, it has scarcely been possible to use the word without a qualifying adjective or subscript. Before the nineteenth century, on the other hand, during the ‘emergence’ of formalized probabilistic thinking, writers from Pascal and Fermat onwards were keenly conscious that the concept they used was often ill-defined and equivocally employed.
There is a sensation, therefore, of sailing unexpectedly into a patch of flat calm when one turns to such early Victorian writers (I use the term in its common, extended sense to refer to the period from around 1830 till the middle of the century) as Lubbock, Drinkwater-Bethune, Galloway, and, above all, De Morgan.
I wish to thank Larry Laudan for his continuing advice and encouragement in the larger research project of which this essay forms a part. I am also grateful to the library staff at The Royal Society, London, for their kind assistance in examining the Herschel Papers deposited there.