David Hume: A Brief Appreciation
by Sean Gabb
(Published in The Salisbury Review, Summer 2004)
In writing about David Hume (1711-76), it is hard to know where to begin. He was a first rate philosopher, historian, economist, political philosopher and literary critic. He was also one of the greatest prose writers of his age. How does one appreciate that achievement – especially as briefly as the space here requires?
One answer is to see his work, in all its diversity, as part of one consistent project. Hume was interested above all in what we can know about ourselves. His philosophy can be seen as a purely negative achievement – as a retreat into scepticism. It is that. But it is also a great clearing away of misconceptions. Most previous thinkers had regarded knowledge as most surely gained by a chain of deduction from undeniable first principles. Hume denied that reason in itself gave any knowledge about the world. For him, there could be no jump – as there was for Descartes – from simple to complex certainties. He rejected the old Platonic distinction between an intelligible world of essences and the world of appearances. Instead, he completed the work of Locke and Berkeley, focussing attention on the world of appearances. Even this, however, could not yield certain knowledge. The evidence of our senses was no more than a stream of sense impressions that might or might not be related to an external reality. These impressions we processed according to conceptions of cause and effect that could not themselves be rationally demonstrated. To say that A caused B for Hume meant only that we had always experienced certain effects one after the other, and that we had a customary expectation that they always would be.
He did not deny the possibility of knowledge. But he did define our capacity to know in far less ambitious terms than it usually had been. There could be no dogmatic certainties, only provisional hypotheses. The test of truth was to be not its inventiveness or its appeal to the emotions, but its economy of hypotheses and its accordance with common sense.
This was the conclusion of his philosophy, and the beginning of his investigations into the world of appearances.
His most important achievement here was to introduce the notion of impersonal laws into the study of mankind. In the previous century, Newton had replaced the mass of speculation on occasional miracles that passed for physics with a few simple laws of motion. These could be used to explain the position of every atom in the universe. By observing human affairs over a long period, Hume believed it possible to arrive at similar laws for ourselves.
Therefore, his writings on history explained events in terms less of individual character than of general tendencies. James I and Charles I, for example, were stupid men who helped bring on a revolution. At the same time, though, the progress of commerce was raising up classes of men who could not be contained within the old order, and was bringing problems of finance and administration that could not be solved in the old ways. Some reconstruction of English government would have happened regardless of who wore the crown or of what he did. Hume was one of the first historians to move away from the chronicle of events inherited from the middle ages, or from the analysis of high politics inherited from the ancient world, towards an understanding of the social and economic tendencies that connected events and that gave shape to the actions of those in and around power.
These laws or tendencies of human nature could be used not simply to explain events, but also to reconstruct them from the distant past. Most famously, he rejected the almost universal belief of his day that the ancient world had been more densely populated than the modern. He looked at the rate of interest on loans, and at the forms and productivity of ancient agriculture. He used a combination of literary sources and linguistic analysis to guess the nature and extent of slavery in the Roman Empire; and he used the known facts of slave reproduction from the Americas to discuss birth rates. He looked at probable death rates. His interpretation of all the evidence pointed to a very sparsely populated Western Empire compared with the France and Italy of his own day. A quarter millennium of further work in historical demography has not shaken his conclusions.
Hume was not original in all his work. There had been intelligent writers on economics and history before he came to those fields. But what he did was to provide a theory of knowledge that justified a search for general laws; and he showed how those laws so far discovered could be unified into a single conceptual framework with which to explain and predict human affairs.
His philosophy stands on its own merits. Indeed, it may be fair to say that the whole of modern philosophy is an argument over the first book of his Treatise of Human Nature (1739). But in other subjects he was eventually eclipsed by his contemporaries or by those who came soon after. In economics he was excelled by Adam Smith, in history by Edward Gibbon, in moral philosophy by Adam Smith and the utilitarians of the next century. For every ten who read them, perhaps only one reads Hume. But it is hard to imagine how, without his own example, they could have written as they did.
To argue for precedence in an age as rich in genius as 18thcentury Europe is perhaps unwise. But any short list of candidates for the title greatest man of the Enlightenment must include David Hume.