the unseen world, taken in their obvious, if not absolutely literal meaning, are not inconsistent with scientific deductions from the Principle of Continuity. We know very well that, especially of late years, a multitude of religious schools have risen up who take many of these expressions in a non-literal and far from obvious acceptation, and who, perhaps, do not accord the same authority to the writers as was formerly done. Into the disputes between these various religious schools we do not pretend to enter, nor do we see that the Shibboleths of such schools can be affected by our arguments, inasmuch as their discussions have, in the great majority of cases, nothing whatever to do with Physical principles. They are rather founded on historical, or moral, or metaphysical considerations, all of which are foreign to our argument. Having no pretensions to a title which we certainly do not covet, we trust that we shall no longer be regarded as theologians either of a narrow and gloomy, or a lax and heretical school, or indeed of any school whatsoever. September 1875. PREFACE TO THE FOURTH AND FIFTH EDITIONS. IN consequence of misapprehensions into which several of our critics have fallen, we have prefixed to this edition an Introduction wherein the objects of our work, and the mode in which we seek to attain them, are fully but compactly explained. We need therefore say nothing on these matters here. The work has been greatly enlarged, and in many parts almost rewritten; but we have nowhere found it necessary to alter or recall any of the statements hitherto made by us. As we now give our names, we can at length complain of the conduct of a London 'Weekly,' which, only a few days after the first appearance of our book, took the (we hope) very unusual course of stating the authorship as a matter of absolute fact, not of conjecture. It was, of course, not authorised to do so, either by ourselves or by our Publisher:and we regret to find that the exigencies of competition for public favour can be thought capable of χχίν PREFACE TO THE FIFTH EDITION. justifying, in the eyes of any one, such a course of conduct. As Professors of Natural Philosophy we have one sad remark to make. The great majority of our critics have exhibited almost absolute ignorance as to the proper use of the term Force, which has had one, and only one, definite scientific sense since the publication of the Principia. As such men are usually among the exceptionally well educated, ignorance of this important question must be all but universal. In addition to what we have said on the subject in the text (§ 97), we would now only mention that the sole recorded case of true Persistency or Indestructibility of Force which we recollect having ever met with, occurs in connection with Baron Munchausen's remarkable descent from the moon. It is, no doubt, a very striking case; but it is apparently unique, and it was not subjected to scientific scrutiny. B. STEWART. P. G. TAIT. April 1876. |