Tocqueville's relevance to sociology derives from at least three features of his thinking: his enormous interest in social observation -- in France, in Britain, in Algeria, and in America; his historical approach to understanding society -- the importance of placing contemporary changes into a historical context; and his causal and comparative imagination -- his desire to discover the causes of some of the patterns and differences he discerned in comparable societies.
I suppose that the books that brought him the greatest recognition reflect these three features of his intellectual persona. Democracy in America combines his appetite for discovering and describing the small but telling details of a society -- the features that mark it as an individual distinct from other contemporary societies, along with an interest in discovering the causes and effects of large features of the societies he observed. This is an intriguing combination of the particular and the general, the small and the large in a modern society. (This feature of his sociological imagination makes me think most of Simon Schama's historical writing -- for example, in Landscape And Memory.) On the side of explanation, Tocqueville was interested in finding the ways in which environment, morality, and civic arrangements combined to produce distinctive patterns of behavior and modes of thought; these become large causal factors in his writings, to which he attributes some of the distinctive features of American values and behavior. And he singled out large features of American society for special study -- democracy, town and village life, the relations among the classes of society, the workings of education, and the workings of American market institutions.
The Ancien Regime and the Revolution illustrates Tocqueville's historical imagination and his effort to place the largest event of the century -- the French Revolution -- into a context of moral and civic factors that combined to make the revolution inevitable. And other lesser books, such as his Recollections of 1848, reflect a combination of these interests in the particular details of a social event with an effort to provide a causal analysis of the way in which it unfolds -- the revolutionary upheavals in Paris in 1848. (These are, of course, the same upheavals to which Marx referred in the Communist Manifesto as the "spectre that is haunting Europe.") It is very interesting to contrast Tocqueville's first-hand observations of the June days of the revolution of 1848, including especially the bloodshed against the workers of Paris, with Marx's more theoretical writings about the same short period of time in The Civil War in France. And it is interesting as well to note that Tocqueville was by no means a neutral observer of these events -- any more than Marx was. Tocqueville was a partisan, supportive of the repression inflicted by the state in the name of order. This too is of some interest when we consider Tocqueville's relation to the founding of sociology.
But in the end, I think it is not a mistake to conclude that Tocqueville brought an important set of ideas to contemporary sociology -- the effort to create a scientific understanding of the modern world. All of the features identified here -- a passion for close observation and description, an interest in the discovery of social causes, an imagination that proceeds through comparison and contrast, and a framework of thought that emphasizes the importance of history -- are in fact useful intellectual components for contemporary sociology. Tocqueville's conservative view of the world certainly interacted with his observations and recommendations. His was certainly not "dispassionate" or value-free social science. But at the same time, we might consider whether a Tocqueville in Shanghai today might not discover some pretty interesting details, processes, and mechanisms that could contribute a deeper sociology of China. And the fact that Tocqueville's thinking did not proceed from the naturalism that motivated others of the founders -- Comte, Spencer, and Durkheim, for example -- is on the positive side of the balance sheet as well. Tocqueville did not operate on the assumption that there must be a single underlying law that explains the processes that he observed in Manchester, Boston, or Algiers; instead, he was content to observe the diversity of the social phenomena he discovered and to tease out some possible, historically limited causal hypotheses about how these historically specific phenomena might work.
So as we reconsider the intellectual composition of the discipline of sociology, it is worthwhile reconsidering Tocqueville.