A rejeição inglesa aos números negativos: uma análise das obras dos principais opositores de 1750 - 1830

Abstract

The main purpose of this research is to review the rich history around the legitimization of negative numbers. It is important to highlight that although negatives were born in Ancient times, their full acceptance as numbers only happened in the XIX century. During this struggle, that lasted almost 2 thousand years, English mathematics, especially the one developed in the second half of the XVIII century and the early XIX century, played a key role as a scenario in which the rejection to negative numbers was fiercer. Therefore, the general purpose of this research is to understand the strong English rejection to negatives that occurred between 1750 and 1830. Consequently, we analyzed the works A Dissertation on the Use of the Negative Sign in Algebra, published in 1758 and Tracts on the Resolution of Affected Algebräick Equations, published in 1800 by Francis Maseres, and Principles of Algebra, published in 1796 by William Frend, as we consider these works as the theoretical basis for those who refused to accept the existence of negative numbers in England by the end of the XVIII century. Besides these two works, we also consider relevant to study the first English work on the Theory of Numbers, An Elementary Investigation of the Theory of Numbers, published in 1811 by Peter Barlow, one of the last ones to adopt a position against negatives in England. Seeking to understand the English rejection to negatives, we set the following specific goals: to identify the theoretical basis of the rejecting stream, analyze the main implications that this rejection posture provoked in the mathematics under development by the end of the XVIII century and study how the rejection theory affected the production of the first English work on the Theory of Numbers. As a result of the analysis developed on Maseres’ and Frend’s works, we concluded that the rejection to negatives was based on the impossibility to clearly and strictly define these numbers within the mathematical concepts that existed in those days. We also noticed that the rejection defended by English mathematicians, on the one hand alerted on the need for a more coherent mathematical substantiation with regards to the theories that were being developed and on the other hand, rejection ideas provoked limitations and restrictions in the mathematics under development by the end of the XVIII century. Among these limitations we highlight those imposed to algebraic operations and the impossibility of having a negative number as an equation root. As for Barlow’s work, research showed that the author’s position against negatives implied the need to adopt strategies to adapt his theory to the limitations imposed by his rejection to negatives. Seeking to improve our knowledge on this issue, we introduce a historical review focused on the use, acceptance, rejection and conception of negative numbers since the early days until the XIX century, when finally the whole controversy was solved with the widening of the concept of number, the axiomatization of algebra and the adoption of modern mathematics as a formal science.