[For example, it] "is a settled dogma of the books that all doubts are to be resolved in favor of the constitutionality of the statute - that the courts will not declare it in conflict with the constitution unless clearly and indubitably driven to that conclusion. But it can not be maintained that such is the actual practice, especially with respect to social legislation claimed to be in conflict with constitutional guaranties of liberty and property ... any one who studies critically the course of decision upon constitutional questions in a majority of our state courts in recent years must agree ... that the courts in practice tend to overturn all legislation which they deem unwise, and ... ‘definitely invaded the field of public policy and are quick to declare unconstitutional almost any laws of which they disapprove, particularly in the fields of social and industrial legislation...’ ...

Another example is to be found in those jurisdictions where the common-law doctrines as to employer’s liability still obtain and in those concerns of employer’s liability in other jurisdictions where recent legislation has left the common law in force. It is notorious that a feeling that employers and great industrial enterprises should bear the cost of the human wear and tear incident to their operations dictates more verdicts in cases of employer’s liability than the rules of law laid down in the charges of the courts. Most of the new trials directed by our highest courts of review because the verdicts returned are not sustained by the evidence are in cases of this sort. Here the law in the books is settled and defined. The law administered is very different, and only the charge of the court, rigidly examined on appeal, serves to preserve an appearance of life in the legal theory ....

.... Another attempt at adjusting the letter of the law to the demands of administration in concrete cases, while apparently preserving the law unaltered, is to be seen in our American ritual, for in many jurisdictions it is little else, of written opinions, discussing and deducing from the precedents with great elaboration. As one reads the reports critically the conclusion is forced upon him that this ritual covers a deal of personal government by judges, a deal of ‘raw equity,’ or, as the Germans call it, of equitable application of law, and leaves many a soft spot in what is superficially a hard and fast rule, by means of which concrete causes are decided in practice as the good sense or feelings of fair play of the tribunal may dictate... We have developed so minute a jurisprudence of rules, we have interposed such a cloud of minute deductions between principles and concrete cases, that our case-law has become ultra-mechanical, and is no longer an effective instrument of justice if applied with technical accuracy. In theory our judges are tied down rigidly by hard and fast rules. Discretion is reduced to a strictly defined and narrowly limited minimum. Judicial law-making has produced a wealth of rules that has exhausted the field formerly afforded for the personal sense of justice of the tribunal. Legally, the judge’s heart and conscience are eliminated. He is expected to force the case into the four corners of the pigeon-hole the books have provided. In practice, flesh and blood will not bow to such a theory. The face of the law may be saved by an elaborate ritual, but men, and not rules, will administer justice...

Some of the causes of divergence between the law in the books and the law in action have been suggested already, In the first place, it is nothing new. Law has always been and no doubt will always continue to be, "in a process of becoming." It must be "as variable as man himself." "Social life," says Wundt, "like all life, is change and development. Law would be neglecting one of its most important functions if it ceased to meet the demands of this ceaseless evolution." However much the lawyer, enamored of his ideal of an absolute certainty in legal rules, may seek to evade these demands, the people will not permit it. Men will do what they are bent on doing, laws and traditions to the contrary notwithstanding. The forms may be kept, but the substance will find some fiction or some interpretation, or some court of equity or some practice of equitable application, to sanction change. Nevertheless, the divergence between law in books and law in action is more acute in some periods of legal history than in others. In all legal systems, periods of growth, periods in which the law is developing through juristic activity, alternate with periods of stability, periods in which the results of the juristic activity of the past are summed up or worked out in detail or merely corrected here and there by legislation.

Closer analysis will reveal three special causes behind the conditions in American law to which I have called attention -- namely, (1) that our settled habits of juristic thought are to no small extent out of accord with current social, economic and philosophical thinking, (2) the backwardness of the art of legislation, particularly in that our legislative law-making, like our judicial law-making, is too rigid, attempts too much detail and fails to leave enough margin for judicial action in individual cases, and (3) the defects of our administrative machinery...." [Roscoe Pound, "Law in Books Law in Action," 44 Am. L. Rev. (1910)].