The cuneiform inscription that serves as our logo and as a design element in Liberty Fund books is the earliest-known written appearance of the word “freedom” (amagi), or “liberty.” It is taken from a clay document written about 2300 B.C. in the Sumerian city-state of Lagash.

      Introduction, annotations, note on the text, index © 2005 by Liberty Fund, Inc.

      Cover art is the Aberdeen detail of the William Roy Map, created from 1747 to 1755, and is used by permission of the British Library (Shelfmark Maps C.9.b.21 sheet 1/2).

      Margin notes have been moved from the margin of the paragraph in the print edition to precede the paragraph in this eBook, in a smaller font.

      This eBook edition published in 2015.

      eBook ISBNs:

       978-1-61487-061-6

       978-1-61487-209-2

       www.libertyfund.org

      CONTENTS

Introduction

A Note on the Text

Acknowledgments

The Principles of Moral Philosophy

       Christian Philosophy

       Bibliography of Works Cited

       Index

INTRODUCTION

      George Turnbull was born on 11 July 1698, probably in the Scottish town of Alloa in Clackmannanshire where his father was the Church of Scotland parish minister. Turnbull entered Edinburgh University in 1711 and continued his studies there till about 1716, though he did not proceed to graduation until 1721, the year in which he became regent at Marischal College, Aberdeen. The regent’s principal task was to instruct a cohort of students in a three-year cycle of studies that included the mathematical and natural sciences, moral philosophy, and natural theology. On becoming regent he inherited a cohort that was already partly through its cycle and that completed it, under Turnbull’s instruction, in 1723. His next cohort, which he taught from 1723 until 1726, included Thomas Reid. During his period as regent, Turnbull became the first of a long line of Scottish moralists to speak explicitly about the introduction of the experimental method of reasoning into moral subjects.

      Turnbull’s teaching had been interrupted by a visit to continental Europe in 1725, when, without the permission of his university, he traveled for a few months in the role of tutor to the Udney family. He was recalled to Marischal and was back at his post by the start of the following year, though in a sense under protest, since he had made it clear in correspondence that, as he put it: “I wish heartily I may be so lucky as to have no more to do with that place.”¹ This fragment of autobiography tells us less about the state of Marischal College than about Turnbull’s restless character—it was a restlessness that dominated his life. In 1727 he left his position and received from the college an honorary LLD (doctorate of laws), the first such degree awarded by Marischal.

      For the next fifteen years Turnbull held a series of short-term jobs, principally as a private tutor. It was an age when the grand tour was in fashion, marked by educational visits to the great capital cities of Europe, and usually culminating in a stay in Rome. As a private tutor he traveled widely, particularly in the Netherlands, France, Germany, and Italy. For the first five of those fifteen years he was tutor to Andrew Wauchope of Niddry, in which role he took his charge to Edinburgh, Groningen and Utrecht, the Rhineland, and France. But by 1733 he was back in Britain. In that year he matriculated and took his BCL degree (bachelor of civil law) at Exeter College, Oxford, conformed to the Church of England, and evidently cultivated clerical contacts assiduously. During the period 1735–37 he was for part of the time in Italy, again as a private tutor, this time to Thomas Watson, son of Lord Rockingham. Between the years 1727 and 1739 Turnbull had spent far more time outside Scotland than in it, and for a significant part of the period had lived in England. He was a deeply religious man, and in 1739 he was ordained into the Church of England, even though he had been raised in a Scottish Presbyterian family. In 1742 he was appointed rector of the parish of Drumachose in Ireland, an appointment he held until his death in 1748, although he did not spend much time there. His preference for travel reasserted itself; however by then, as we shall see, health considerations may also have played a role. In 1744 he returned to Italy where, among other things, he was involved in the covert gathering of information on exiled Scottish Jacobites.²

      Turnbull was a prolific writer, with a particular interest in the themes of morality, religion, and liberal education.³ His earliest publication was a graduation thesis on the need for moral philosophy to be accepted as a science along with all the other empirical sciences, and to be developed with the aid of the same methodology as that employed for the other sciences.⁴ This theme recurs in his writings and is especially conspicuous in the present work.

      The relation between the two volumes of The Principles of Moral and Christian Philosophy (1740), separately entitled Principles of Moral Philosophy and Christian Philosophy, respectively, is problematic because the first volume does not declare itself on the title page to be volume one, whereas the second volume does declare itself to be volume two, but only so declares itself in some copies, not all; and where the title page bearing the composite title The Principles of Moral and Christian Philosophy does appear in volume two that page has been glued in as a separate leaf and is plainly not part of the original printing plan. The reason for this is almost certainly that John Noon, the publisher of volume two,⁵ thought belatedly that Turnbull’s new work, Christian Philosophy, would have a better chance of commercial success if it were marketed as volume two in relation to the Principles of Moral Philosophy. But even if the composite title represents a marketing ploy, there is nonetheless an impressive unity of purpose to the two volumes taken together; in an obvious sense the second takes up and advances the discussion of the first. And there is little doubt that the two volumes were seen by Turnbull himself as two parts of a unitary work.

      Furthermore, the first volume ends with an “advertisement” declaring: “So soon as the Author’s Health permits, will be published, CHRISTIAN PHILOSOPHY: or, The CHRISTIAN DOCTRINE concerning PROVIDENCE, VIRTUE, and a FUTURE STATE, proved to be perfectly agreeable to the PRINCIPLES OF MORAL PHILOSOPHY.” And Christian Philosophy does indeed seek to do exactly what the advertisement declares. It is therefore probable that, whatever the publisher’s motive for inserting the composite title in some copies of volume two, the two volumes were, according to the author’s intention, a single book.

      In light of the advertisement it might be speculated (without being strongly urged) that the discrepancy in title pages