Natural Philosophy and a New World Picture

by Stephen Gaukroger

The core question dealt with in The Collapse of Mechanism and the Rise of Sensibility concerns the way in which, and the extent to which, natural philosophy comes to occupy the position of the paradigm bearer of cognitive values in the period between the 1680s and the middle of the eighteenth century, thereby offering a model for all other cognitive endeavours.

There are two issues, as indicated in the title of the book. As regards the collapse of mechanism, many of the issues hinge on the question of systematic versus non-systematic understanding. The dominant natural-philosophical system in the mid to late seventeenth century, Cartesian mechanism, had proceeded on the assumption that the way to pursue natural philosophy was via systematic matter theory. The aim of Cartesian mechanism was to provide a single, unified, comprehensive account of natural phenomena in terms of their underlying corpuscular micro-structure: all macroscopic physical processes were to be accounted for in terms of mechanically-described interactions between micro-corpuscles. From the 1680s onwards, however, it became increasingly difficult to see how the mechanist project might be realized, and mechanical explanation degenerated into promissory notes when it came to recalcitrant phenomena such as gravitation, electricity, magnetism, and chemical reactions. At the same time, there emerged a broadly Lockean stream of thought that insisted that the unificatory project to which mechanism subscribed was based on a misunderstanding of the nature of physical enquiry.

The new generation of natural philosophers, particularly after the 1730s, rejected the conception of natural philosophy offered by mechanists such as Descartes, who had in effect thought of what they were doing as a successful realization of a project that at the most basic level was much the same as that of Aristotle, namely the provision of an account of the nature and behaviour of matter. By contrast, the new generation conceived of what they were doing as something completely different from the aims and aspirations of the Aristotelian project. Amongst other things, they did not automatically associate the physical and the material. In the process, the efforts to replace the old Aristotelian principle of the unity of physical enquiry with a new one were abandoned. Indeed, as Locke’s ideas—treated by many as a philosophical mirroring and clarification of the methodological rationale behind Newton’s physical theory—were taken up, it became increasingly clear that the structural features of natural-philosophical enquiry that issued in its explanatory success had nothing to do with any assumed explanatory unity. Quite the contrary, they were due in many cases to a refusal to confine physical explanation to reduction to some fundamental microscopic level of matter. What emerged from this was a form of explanatory pluralism, in which the various forms of physical enquiry had only a loose, indirect, and changing relationship with one another.

But if natural philosophy is not a single unified structure, but simply a loose grouping of disciplines with different subject matters and different methods, tied in various ways each of which work for some purposes but not for others, then there can be no modelling of cognitive values generally on scientific ones. We can in fact identify a number of cases where appeal to more fundamental principles is manifestly counterproductive, and the two most comprehensive eighteenth-century attempts at reduction—the attempt to reduce physics generally to mechanics, and the attempt to reduce chemistry to corpuscular matter theory—are not only manifest failures, but they give every appearance of artificially imposing a wholly inappropriate conception of the unity of the discipline.

At the same time, there emerged a new conception of natural philosophy, one in which sensibility took over the role previously occupied by reason, answering to the needs of a general model for cognition in a more satisfactory way, not least in that the notion of sensibility tied together developments in natural philosophy, philosophical psychology, literary culture, and moral and political theory. As far as natural philosophy was concerned, the crucial developments occurred in physiology, where phenomena such as muscle irritability and nervous sensibility not only defied appeal to biomechanics, but suggested that matter itself was essentially active and sensitive, a view apparently confirmed by the discovery of the reproductive behaviour of the polyps, which had the capacity to regenerate the whole organism from slices cut from the original. However, it was not simply a question of substituting a new content and leaving the general structure of the model fixed. Quite the contrary, if, as Diderot and others claimed, sensibility actually underlay cognition, this had fundamental implications for our understanding of our relation to the world. In particular, whereas the conception of natural philosophy as an embodiment of reason suggested that there might be a single cognitive account of the world and our place in it, taking sensibility seriously opened up the possibility that there may need to be many different forms of understanding of the world, and the propositional form represented by ‘reason’ may need to be supplemented by various non-propositional forms of understanding, forms which captured the kinds of relation we have to the world in our fears, anxieties, aspirations, desires etc. Above all, a number of questions that had traditionally been dealt with either in humanist or ‘civic’ terms, or in terms of Christian teaching, but in which considerations of sensibility had played an increasing role, now began to fall under the new expanded cognitive model, especially to the extent to which this embodied and sanctioned a form of anthropology.

What was particularly significant here was the recognition of a historical dimension to knowledge—something completely alien to the mechanist model, which was dismissive of historical study—which effected the beginnings of a new connection between natural philosophy and humanistic learning. Traditional historical writing itself underwent a transformation in the seventeenth and eighteenth centuries, and Voltaire had starting writing history, not least in his history of manners, in terms of issues rather than events. At the same time, historicization crept into the core of natural philosophy in 1749 with the publication of Buffon’s Histoire naturelle, which sought to understand biological structure through genesis instead of through essence or conventional classification, with a view to putting developmental concepts at the centre of natural-philosophical thinking more generally. The understanding of Christianity was also affected by these developments. Biblical chronology had provided a timeframe for the history of the earth (and more generally the history of the cosmos) which Buffon rejected, proposing much longer timeframes to allow the sequence of geological events that he postulated had led to the earth in its present state. There had also been developments since the middle of the seventeenth century offering conjectural histories of superstition and of religion, which inevitably came to be associated with one another, and which acted to contextualize and historicize Christianity, rendering its claims open to scrutiny, and possible replacement, on a broad front.

Compounding these developments was the gradual replacement of both Christian and civic humanist conceptions of human nature and basic moral values with a form of naturalized anthropology in which collective human behaviour—most notably in political and economic contexts but also in religious ones—is accounted for in way that ignores what traditional accounts would have regarded as moral questions deriving from the intentions of the agents whose behaviour is being studied. This is nowhere more evident than in the emergence of the ‘moral sciences’, where questions of human behaviour begin to be formulated in a novel way, one in line with the kind of anthropological conception fostered in the newly reformed natural-philosophical model of understanding. In this way, a number of developments converged in the mid-eighteenth century to tie natural philosophy in with questions that, up to this point, would have been considered wholly independent of it. As a direct result of this, natural philosophy moves to the centre of attempts to understand the world and our place in it.

About the Author:

Stephen Gaukroger has been in the Philosophy Department at the University of Sydney, where he is currently Professor of History of Philosophy and History of Science, since 1981. He was elected a Fellow of the Australian Academy of Humanities in 1992, and awarded the Australian Centenary of Federation Medal for Contribution to History of Philosophy and History of Science, 2003.  

His research is centred around a long-term project on the emergence and consolidation of a scientific culture in the West in the early modern era, and is presently working on the persona of the philosopher in the modern era.