Edgeworth's Approach to Economics
The obvious dominant characterised of Edgeworth's approach to economics is that it is mathematical, characterised by an original use of techniques, although he does not appear to have received a formal training in mathematics.
However, he came to economics from moral philosophy. The central question of distributive justice, rather than simply the application of mathematics, dominated his attitude towards economics. His main argument was that mathematics provided powerful assistance to “unaided” reason, and could check the conclusions reached by other methods. For example, he suggested that ‘he that will not verify his conclusions as far as possible by mathematics, as it were bringing the ingots of common sense to be assayed and coined at the mint of the sovereign science, will hardly realise the full value of what he holds' (Edgeworth 1881: 3).The contrast between Edgeworth and Marshall was sharp. Although both men turned to economics from mathematics and moral philosophy, Marshall generally used biological analogies, and was concerned with developing maxims. In contrast, Edgeworth generally used mechanical analogies, and was more concerned with arriving at theorems. Pigou commented that, ‘during some thirty years until their recent deaths in honoured age, the two outstanding names in English economics were Marshall...and Edgeworth... Edgeworth, the tool-maker, gloried in his tools. Marshall, on the other hand, had what almost amounted to an obsession for hiding his tools away' (Pigou quoted in Pigou and Robertson 1931: 3). Edgeworth's interest in the natural sciences often led him to make comparisons with scientific laws, and especially to show that the physical sciences also relied on abstraction and approximation.
Edgeworth argued carefully that the assumptions used in economics are often untestable, and he therefore took precautions against the accusation of “plucking assumptions from the air”.
He was conscious of the fact that the difficulty is in making the crucial abstractions which make the particular problem under consideration tractable, but which are not question-begging. His attitude to many a priori assumptions was influenced by his approach to statistical inference. He referred to, ‘the first principle of probabilities, according to which cases about which we are equally undecided...count as equal' (Edgeworth 1881: 99). Thus, the appropriate assumption was that all feasible values, say of elasticities, were equally likely, until evidence is obtained or reference may be made to ‘the consensus of high authorities' (Edgeworth 1925, ii: 391). This also illustrates Edgeworth's attitude to authority and his many allusions to the views of other leading economists. Price (1946: 38) referred to his frequent ‘reference to authority for...support of tentative opinion waveringly advanced'.Edgeworth was also prone to stressing negative results. For example, in discussing taxation, where the criterion of minimum sacrifice does not alone provide a simple tax formula, he stated:
Yet the premises, however inadequate to the deduction of a definite formula, may suffice for a certain negative conclusion. The ground which will not serve as the foundation of the elaborate edifice designed may yet be solid enough to support a battering-ram capable of being directed against simpler edifices in the neighbourhood (Edgeworth 1925, ii: 261).
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