Nothing can be more helpful to the coming generations of physicians than a wholesome realization of the futility and occasional danger of dogmatism in their fields of endeavor. The development of a reasonably critical attitude of mind may not be compatible with the inertia of intellectual contentment; it is usually far easier to accept the traditional statement and act in accordance with it than it is to modify one's performance in the light of diligent inquiry. Nevertheless, it requires a mind open to radical changes for participation in that which is designated as progress. New discoveries and constructive thinking lead to evolution of knowledge and revolutionary practices. Advancement in professional fields means the abandonment of much that is old and the avoidance of unpromising avenues. Since practice, in medicine, is often based on dogmatic pronouncements, it is likely to fail in its objects when the premises become unstable.