Either Theism is true or false. If true, discussion must help to spread its influence; if false, the sooner it ceases to influence human conduct the better for human kind. This Plea for Atheism is put forth as a challenge to Theists to do battle for their cause, and in the hope that, the strugglers being sincere, truth may give laurels to the victor and the vanquished: laurels to the victor, in that he has upheld the truth; laurels which should be even more welcome to the vanquished, whose defeat crowns him with a truth he knew not of before. APPENDIX A few years ago a Nonconformist minister invited me to debate the question, “Is Atheism the True Doctrine of the Universe?” and the following was in substance my opening statement of the argument, which for some reason, although many letters passed, was never replied to by my reverend opponent. “By Atheism I mean the affirmation of one existence, of which existence I know only mode; each mode being distinguished in thought by its qualities. This affirmation is a positive, not a negative, affirmation, and is properly describable as Atheism because it does not include in it any possibility of _Theos_. It is, being without God, distinctly an Atheistic affirmation. This Atheism affirms that the Atheist only knows qualities, and only knows these qualities as the characteristics of modes. By ‘existence’ I mean the totality of phenomena and all that has been, is, or may be necessary for the happening of any and every phenomenon. By ‘mode’ I mean each cognised condition (phenomenon or aggregation of phenomena). By ‘quality’ I mean that characteristic, or each of those characteristics, by which in thought I distinguish that which I think. The word ‘universe’ is with me an equivalent for ‘existence.’