The design of the following essay is to consider, in a short and direct way, some of the limits that are set by sound reason to the practice of the various arts of accommodation, economy, management, conformity, or compromise. The right of thinking freely and acting independently, of using our minds without excessive awe of authority, and shaping our lives without unquestioning obedience to custom, is now a finally accepted principle in some sense or other with every school of thought that has the smallest chance of commanding the future. Under what circumstances does the exercise and vindication of the right, thus conceded in theory, become a positive duty in practice? If the majority are bound to tolerate dissent from the ruling opinions and beliefs, under what conditions and within what limitations is the dissentient imperatively bound to avail himself of this toleration? How far, and in what way, ought respect either for immediate practical convenience, or for current prejudices, to weigh against respect for truth? For how much is it well that the individual should allow the feelings and convictions of the many to count, when he comes to shape, to express, and to act upon his own feelings and convictions? Are we only to be permitted to defend general principles, on condition that we draw no practical inferences from them? Is every other idea to yield precedence and empire to existing circumstances, and is the immediate and universal workableness of a policy to be the main test of its intrinsic fitness? To attempt to answer all these questions fully would be nothing less than to attempt a compendium of life and duty in all their details, a Summa of cases of conscience, a guide to doubters at every point of the compass. The aim of the present writer is a comparatively modest one; namely, to seek one or two of the most general principles which ought to regulate the practice of compliance, and to suggest some of the bearings which they may have in their application to certain difficulties in modern matters of conduct.