[7] See p. 287 of this volume. CONTENTS PAGE I. PROLOGUE 1 (_Controverted Questions_, 1892). II. SCIENTIFIC AND PSEUDO-SCIENTIFIC REALISM [1887] 59 III. SCIENCE AND PSEUDO-SCIENCE [1887] 90 IV. AN EPISCOPAL TRILOGY [1887] 126 V. THE VALUE OF WITNESS TO THE MIRACULOUS [1889] 160 VI. POSSIBILITIES AND IMPOSSIBILITIES [1891] 192 VII. AGNOSTICISM [1889] 209 VIII. AGNOSTICISM: A REJOINDER [1889] 263 IX. AGNOSTICISM AND CHRISTIANITY [1889] 309 X. THE KEEPERS OF THE HERD OF SWINE [1890] 366 XI. ILLUSTRATIONS OF MR. GLADSTONE'S CONTROVERSIAL METHODS [1891] 393 I: PROLOGUE [_Controverted Questions_, 1892] Le plus grand service qu'on puisse rendre à la science est d'y faire place nette avant d'y rien construire.--CUVIER. Most of the Essays comprised in the present volume have been written during the last six or seven years, without premeditated purpose or intentional connection, in reply to attacks upon doctrines which I hold to be well founded; or in refutation of allegations respecting matters lying within the province of natural knowledge, which I believe to be erroneous; and they bear the mark of their origin in the controversial tone which pervades them. Of polemical writing, as of other kinds of warfare, I think it may be said, that it is often useful, sometimes necessary, and always more or less of an evil. It is useful, when it attracts attention to topics which might otherwise be neglected; and when, as does sometimes happen, those who come to see a contest remain to think. It is necessary, when the interests of truth and of justice are at stake. It is an evil, in so far as controversy always tends to degenerate into quarrelling, to swerve from the great issue of what is right and what is wrong to the very small question of who is right and who is wrong. I venture to hope that the useful and the necessary were more conspicuous than the evil attributes of literary militancy, when these papers were first published; but I have had some hesitation about reprinting them. If I may judge by my own taste, few literary dishes are less appetising than cold controversy; moreover, there is an air of unfairness about the presentation of only one side of a discussion, and a flavour of unkindness in the reproduction of "winged words," which, however appropriate at the time of their utterance, would find a still more appropriate place in oblivion. Yet, since I could hardly ask those who have honoured me by their polemical attentions to confer lustre on this collection, by permitting me to present their lucubrations along with my own; and since it would be a manifest wrong to them to deprive their, by no means rare, vivacities of language of