THIS IS A TIME of decision for the races of men. Social forces are at work testing whether individual liberty and freedom shall perish under the iron shod heel of the dictator or maintain their place in the sun through valiant battle. Both wishful thinking and material evidence assure us that man may still expect to enjoy his own house as his private castle and his own thought mechanism as the arbiter of his philosophy. Some of the threatening forces are offensively obtrusive mid generally recognized. Other enthralling elements are less generally recognized, although likewise plainly visible. The former components, largely political, are already being attended to by millions. The particular force of the latter group, to which this volume is addressed is nonpolitical and exists in the realm of natural science. It concerns freedom of thought and opinion in the matter of biological theories. In order to bring this force into the clear, let us outsider for a moment some animate object in our immediate environment. Because of his familiarity, let us select the common tree squirrel. For a number of reasons this squirrel is an intriguing animal. He may arouse our displeasure by showing a liking for things which we wish for ourselves, or he may draw our admiration through his lively actions and chic and mischievous appearance. Some see in him merely an object of the passing moment. Others observe the numerous adaptations he shows for his life in the trees, such as his quick eye, his supple muscles, his fine sense of balance, his facile feet with their all-important claws, and his flexible tail. This specific adequacy for his environment arouses questions in the minds of many observers which lead to long and careful study. This study will result in the formulation of a certain philosophy of life with regard to the tree squirrel. Although we live in an age of great complexity in which division and subdivision of everything are omnipresent, still, in regard to these philosophies, it is refreshing to find that they all fall into one or the other of two groups. The observer’s philosophy will either explain the nimbleness and alacrity of the squirrel in the tree as the result of an evolutionary process through which the animal has developed from a simple, possibly one-celled form into this efficient complexity, or will assume that the squirrel was created a squirrel by a Supreme Intelligence who shaped him to fit nicely into the arboreal environment. We would like to think that a man is free to hold to one or the other of these philosophies with impunity as concerns the judgments and harsh opinions of his fellow beings. However, such is not the case. There has developed in recent years among our scientists an attitude of mind which amounts to a considerable force at certain times in certain situations. This-attitude is epitomized in the following quotation from HH Newman: