The invention of the concept of social surplus: Petty in the Hartlib Circle*

Abstract

Among other innovative and important contributions to the formation of political economy, William Petty is the originator of the concept of an economic or social surplus, a vital element in the formation of classical economics. It therefore is a natural and intriguing question, how Petty came to develop his seminal formulations of surplus. Our argument is that the concept took form in his thought as a result of stimulus provided by Petty's involvement in the agricultural technology programme of Samuel Hartlib and his ‘Circle’.

Keywords:

• Classical economics
• seventeenth century
• surplus
• William Petty

Notes

 *  The author is indebted to D.D.C. Chambers, C. Gehrke (also for assistance with some German manuscripts), F. Harris, H.D. Kurz, A. Roncaglia, M.L. Smith and two anonymous referees for helpful comments – and to staff of the British Library, and the Baillieu Library in the University of Melbourne, for assistance (especially P. Condron) – without thereby implicating any of them in the final product.

Webster (1975) extensively discusses Petty in, and influenced by, the Hartlib Circle. McNally (1988: 35 – 40, 44 – 45, 48) has argued in general terms for the role of the Bacon-inspired Hartlib agricultural technology programme in shaping Petty's ‘embryonic scientific economics’, following Webster's lead.

The production of a non-negative surplus of every commodity is not strictly necessary to a rigorous reconstruction of the classical surplus approach, applied to income distribution and price determination. Only a weaker viability condition is required: that the production system is capable, in principle, of at least self-replacement of its inputs (Sraffa 1960: 5n). The use of particular commodities can decline over time, even disappear. In such circumstances the aggregate, system-wide input quantities of some commodities can exceed the same commodities' outputs, for some time periods, in entirely viable systems. This possibility is not considered by Petty and will also be put aside here.

For citation practice with regard to the Hartlib Papers documents, see the Appendix below. The letter presumably belongs to early 1649. More's reply of March 1649, written to Hartlib, sneers at the materialism: ‘… Mr Petty would measure the worth of all Philosophy by what it can procure for your back, bed and bord. Wee shall be a common wealth of rarely improved beastes, not of learned men’ (28). The first sentence, as such, is false; but there is a measure of truth in More's response as well. He further comments that virtue (variously conceived) is more important to human wellbeing ‘than all that the witt of any mortalls can dig <out> for their own ease and welfare, though they would teare Natures gutts out, and see her very heart beat’ – and that to suppose what Descartes has written to be of no use, is to say ‘that the measure of all must be the back and the belly, that is all bodily conveniences … a wretched and pittifull aphorisme’. Petty's letter itself expresses admiration for Descartes. See also Petty's later list of great modern thinkers, which includes Descartes (Lansdowne 1928: 158; cf. Aspromourgos 1996: 54). Transcripts of the two letters are published in Webster (1969: 367 – 72). Ironically, More himself later became an opponent of Cartesianism (Webster 1969: 359 – 60, 376 – 77).

The British Library copy is at Add. MSS 4292: ff. 141r – 42v, and is headed ‘A Coppy of a Phytologicall Letter written to M^r S Hartlib.’ – in a different hand to the document itself. Below this and towards the right margin there is written in yet another hand: ‘Quere written by Sir W. Petty’. The Hartlib Papers copy has the manuscript inventory reference no. 8/22/1A – 4B and is headed ‘A Copy of a Phytologicall Letter, written to Mr Hartlib.’ (The title provided by the CD-ROM itself is ‘Copy Letter in Hand H, ? to Hartlib’.) Hereafter the latter is cited as ‘Phyt.’. Murray (1909: 812) defines phytology as ‘[n]ow rare … [t]he science of plants; botany’ – with usages from 1658, 1819, 1849 and a Latin variant of 1647 (phytologia). Neither copy is dated; but at Phyt.: f. 1A the writer refers to his thoughts on this subject as a comment on ‘those … Qveries … made by your late … Friend, in the 38. page of your Legacy (according to the last Edition.)’. The work being referred to, Samuel Hartlib His Legacie …, went through three editions (1651, 1652, 1655). The author of the first part of this work including p. 38 is thought to be Robert Child, who apparently died in early 1654 (49). This points to the reference being to the 1655 edition, thereby placing the phytology letter at or after that date. Further confirming this judgement, p. 38 of that edition is new text, not in the second edition – a long, single paragraph concluding a section and taking up the whole page, which laments the prevailing ignorance of the causes of land fertility (articulated precisely as a series of queries) and invites others to contribute knowledge.

Under the second class, among ‘many others’, the writer lists: hemp, flax, madder, ode, saffron, wine, sugar, oil, malt, figs, prunes, prunellos, raisins, currants, French barley, oatmeal, rice, indigo, cochineal, sap-green, turnsole, paper, spunk, birdlime, starch, aloes, socotorine, opium, asafoetida, tobacco, scammony and gamboge (Phyt.: f.3A). The strangely large number of the examples here that are dyeing agents may be read as some further circumstantial evidence for Petty's authorship: he presented a paper to the Royal Society on this topic (Petty 1667). It may be added that throughout the Ephemerides there is widespread use of the term oeconomica to describe elements of the Hartlib intellectual programme. (Cf. Aspromourgos 2001: 83 – 85, for Petty's various uses of `economy', one of which involves a similar distinction – between physico-mathematical and economic parts of a scientific discourse.) Also, at a number of points in Phyt. (ff. 1B, 2A, 3A) the writer speaks of quantities of agricultural output occurring without any input of human labour. There is an echo of this notion – in the distinction between outputs resulting without and with a contribution of human labour – in one of Petty's attempts at a ‘par of value’ between land and labour (Petty 1691a: 180 – 81; Aspromourgos 1996: 93, 99).

The two letters are located at British Library Add. MSS 15948: f. 66r – v, and Vaughan (1839, vol. 2: 463 – 64). These are two of only four further references to phytology (i.e. apart from the phytology letter itself) in the entire digital archive, which virtually guarantees that they are references to our phytology letter rather than some other.

By this term (which is not from the primary literature) I mean the following: (1 – a_cc )/a_cc , where a_cc is the direct input per unit of output of a commodity c (say corn) in the production of itself, whether or not other inputs are also employed in its production (cf. Bharadwaj 1970: 419, 426). (This is not to be confused with the concept of commodity- or own-rates of interest.) In the terms employed for single production in section 2 above, the own-rates of reproduction are (A – A_a )/A_a , (B – B_b )/B_b – putting aside necessary labour consumption, for the moment (see section 6). The primary literature employs what may be called the concept (not the term), gross own-rates – (1/a_cc ) rather than [(1/a_cc ) – 1].

For other references to Petty of a general technological nature (in many instances, slight), see documents C – F, H, L, N – O, R – S, and letters 2 – 8, 10 – 11, 13, 16, 20, 23, 29, 31, 33, 36, 38, 40, 43, 45 – 47, 49, 51, 53, 55 – 56, 60 – 64, 66, 71 – 75 and 93 – 94. The second part of document R, on music, is really about memory. Petty records the case of a person who, after one perusal, can recall every note of a piece of music, adding that this facility could be applied ‘to remember euery Ingredient and quantity thereof going into any Medicinall composition at first hearing’. This points to the character of medical compounds or preparations, as an expression of input – output methods or recipes (most certainly generally written down on paper) – and thereby allows the speculation that Petty's medical background also encouraged him towards writing down production systems as arrays of inputs and outputs.

Given the language in which Petty articulates these thought experiments, ‘corn’ could also be conceived of as a composite commodity, pointing to the notion of a ‘vertically integrated wage-goods sector’ (Garegnani 1984: 313 – 20; or 1987: 570 – 73).

The ‘non-necessary’ industry b could itself employ input of commodity b, subject to further restrictions – most obviously, a positive own-rate of reproduction of b (vide Sraffa 1960: 7 – 8, 90 – 91; Kurz and Salvadori 1995: 104 – 10). In addition, it may be observed, in relation to some comments made in section 2 above, that Petty does not himself explicitly treat land as leaving the production process in the same quantity and quality as it entered.

This kind of simplifying approach has been described as a corn-silk model, where ‘silk’ represents luxury, or non-necessary, or ‘non-basic’ commodities (Kurz and Salvadori 1995: 58, 85 – 86). (Sraffa 1960: 8 constructs the concept of non-basics for commodities that do not directly or indirectly enter into the production of all commodities – and also mentions silk as an example.) The metaphor of ‘silk’ for non-basic commodities is peculiarly appropriate in relation to Petty: lawyers are one of his favourite examples of non-necessary labour. They were a class of labour with whom he had considerable and unwelcome personal involvement, though arguably largely self-inflicted. In the English tradition ‘silk’ is itself a metaphor for a certain subclass of lawyers.

For von Neumann's notion of self-reproducing machines see von Neumann (1966: e.g., 92 – 3, 118 – 26, 286 – 96). For his growth model, and its relation to classical economics, see von Neumann (1937) and Kurz and Salvadori (1995: 403 – 26) – or for a very valuable fuller version of the latter argument, Kurz and Salvadori (1993). It may be added that to the extent that Petty's more realistic treatments of surplus in terms of multiple basic commodities are in unpublished writings, they could not have influenced later writers in the tradition who had no access to them – in particular, those who came most immediately after him (Cantillon and Quesnay). Cantillon's brilliance sufficed to carry the analysis of intersectoral commodity flows to new levels of analytical insight, with just the published Petty analyses as his point of departure.

I say ‘to the best of my knowledge’ because this has been effected via electronic search of the digital archive, including search via variants of Petty's name (e.g. ‘peti’). This therefore may miss references to him, which do not refer to his name at all. There are also in the archive copies of three printed documents connected with Petty: Love (1658); Petty (1648a); and Petty (1648b). The last of these, among other things, is an important extended statement of the ‘history of trades’ project.

HROnline (2002) The Hartlib Papers: A Complete Text and Image Database of the Papers of Samuel Hartlib (c. 1600 – 1662) Held in Sheffield University Library, Sheffield, UK. Sheffield, UK: Humanities Research Institute, University of Sheffield.

Because of the presence of copy letters and copy extracts, there is a slight element of arbitrariness in the distinction between letters and other documents.

Letter 36 appears twice in the CD-ROM – the original is in the Yale collection and a copy letter is in the physical Sheffield collection. There are also two copies of each of letters 11 and 34 in the physical archive itself, though the latter duplication is only partial (see 33/2/19A with 26/33/7A). Because no names attach to them at all, inventory reference numbers are appended to letters 65 and 89.