The Lord Chief Justice then dealt with the question whether conjugal prudence was in itself immoral, and pointed out to the jury that the decision of this very serious question was in their hands: 

“A man and woman may say, ’We have more children than we can supply with the common necessaries of life:  what are we to do?  Let us have recourse to this contrivance.’  Then, gentlemen, you should consider whether that particular course of proceeding is inconsistent with morality, whether it would have a tendency to degrade and deprave the man or woman.  The Solicitor-General, while doubtless admitting the evils and mischiefs of excessive population, argues that the checks proposed are demoralising in their effects, and that it is better to bear the ills we have than have recourse to remedies having such demoralising results.  These are questions for you, twelve thinking men, probably husbands and fathers of families, to consider and determine.  That the defendants honestly believe that the evils that this work would remedy, arising from over-population and poverty, are so great that these checks may be resorted to as a remedy for the evils, and as bettering the condition of humanity, although there might be things to be avoided, if it were possible to avoid them, and yet remedy the evils which they are to prevent—­that such is the honest opinion of the defendants, we, who have read the book, and who have heard what they have said, must do them the justice of believing.  I agree with the Solicitor-General if, with a view to what is admitted to be a great good, they propose something to the world, and circulate it especially among the poorer classes, if they propose something inconsistent with public morals, and tending to destroy the domestic purity of women, that it is not because they do not see the evils of the latter, while they see the evils of the former, that they must escape; if so, they must abide the consequences of their actions, whatever may have been their motive.  They say, ’We are entitled to submit to the consideration of the thinking portion of mankind the remedies which we propose for these evils.  We have come forward to challenge the inquiry whether this is a book which we are entitled to publish.’  They do it fairly, I must say, and in a very straightforward manner they come to demand the judgment of the proper tribunal.  You must decide that with a due regard and reference to the law, and with an honest and determined desire to maintain the morals of mankind.  But, on the other hand, you must carefully consider what is due to public discussion, and with an anxious desire not, from any prejudiced view of this subject, to stifle what may be a subject of legitimate inquiry.  But there is another view of this subject, that Knowlton intended to reconcile with marriage the prevention of over-population.  Upon the perusal of this work, I cannot bring myself to doubt that he honestly believed that the remedies he proposed were less evils than even celibacy or over-population on the one hand, or the prevention of marriage on the other hand—­in that honesty of intention I entirely concur.  But whether, in his desire to reconcile marriage with a check on over-population, he did not overlook one very important consideration connected with that part of society which should abuse it, is another and a very serious consideration.”