Legal realism is a naturalistic approach to the law. He is of the view that case law should imitate the methods of the natural sciences, i.e. be based on empirical evidence. Hypotheses must be tested against the observations of the world. [Citation needed] Holmes is a preeminent figure in American legal thought for many reasons, but what realists have learned most from Holmes is his famous theory of predicting the law, his utilitarian approach to legal reasoning, and his “realistic” insistence that judges don`t simply draw legal conclusions with relentless, mechanical logic when deciding cases, but are influenced by ideas of fairness. public order, prejudices and experiences. In the first paragraph of The Common Law, he wrote: Realism was established for much of the late 20th century thanks to H.L.A. Hart`s misunderstanding of the theory is treated as a conceptual claim.  Hart was a philosopher of analytic law who was interested in the conceptual analysis of concepts such as the concept of “law.” It was necessary to identify the necessary and sufficient conditions for the use of the term “law”. When realists like Oliver Wendell Holmes pointed out that people involved in the legal system generally wanted to know what was going to happen, Hart assumed that they offered the necessary and sufficient conditions for the use of the term “law.” Nowadays, legal theorists tend to realize that realists and conceptual jurists were interested in various issues. Realists are interested in methods to more accurately predict judges, while conceptual lawyers are interested in the correct use of legal terms. Next, Holmes presents his most important and influential argument, the “bad man” theory of the law: “If we consider our friend`s point of view to be a bad person, we will find that he does not care about two straws,” neither about the morality nor the logic of the law.
For the evil man, “legal duty” means only “a prophecy that if he does certain things, he will face unpleasant consequences through imprisonment or forced payment.”  The villain does not care about legal theories and only cares about practical consequences. In the spirit of pragmatism, Holmes suggests that this is a useful way to discover the true meaning of legal terms. Because of their worthless approach, legal realists are against the traditions of natural law. Legal realists argue that these traditions are historical and/or social phenomena and that they should be explained by a variety of psychological and sociological assumptions, with legal phenomena determined by human behavior that should be studied empirically rather than according to theoretical assumptions about the law. As a result, legal realism contrasts with most versions of legal positivism. Legal realism was primarily a reaction to the legal formalism of the late 19th and early 20th centuries and was the predominant approach for much of the early 20th century. His negative effort succeeded in challenging the formalistic assumptions that judges have always done what they have said, so that it is often said that “we are all realistic now.” However, realism failed in its positive quest to find a better way to predict how judges would behave than to rely on the reasons given by judges. This essay exposes the main elements of the revisionist and philosophical interpretation of the jurisprudence of American legal realism that I have developed in a number of articles over the past decade. The revisionist reading also debunks some popular myths about legal realism, such as the following: realists believed that “what the judge ate for breakfast determines the decision”; a critique of the distinction between public and private was a central element of the realist jurisprudence; and realists were attached to an inconsistent form of rule skepticism. A theory of law and legal reasoning that emerged in the early decades of the twentieth century is largely characterized by the assertion that the law is best understood when one focuses on what judges actually do to decide cases, rather than what they say they do.
 The central objective of legal realism was legal formalism: the classic view that judges do not make a law, but apply it mechanically, drawing logically clearly correct legal conclusions from a set of clear, coherent and comprehensive legal rules. American legal realism has been aptly described as “the most important indigenous legal movement in the United States during the twentieth century.”  “Makes a valuable contribution to our understanding of American legal realism by reshaping the `ideas in context` approach to intellectual history. Schlegel`s study of the social science engagement of these professors and institutions is comprehensive and penetrating, providing a wealth of factual information and solid analysis. –American Historical Review As a form of jurisprudence, legal realism is defined by its emphasis on law as it actually exists in practice, rather than how it exists in books. To this end, it dealt primarily with the actions of judges and the factors that influenced judicial decision-making processes. As Karl Llewellyn argues, “[t]he decisions are made by the judges; Judges are men; As men, they have a human past.  Law therefore did not exist in a metaphysical realm of fundamental rules or principles, but was inextricably linked to human action and the power of judges to determine law. To understand the decisions and actions of legal writers, legal realists turned to social science ideas to understand human behavior and relationships that resulted in a particular legal outcome.  Legal realism is associated with American jurisprudence in the 1920s and 1930s, particularly among federal judges and lawyers within the Roosevelt administration. Notable jurists associated with legal realism included Felix Cohen, Morris Cohen, Arthur Corbin, Walter Wheeler Cook, Robert Hale, Wesley Hohfeld, Karl Llewellyn, Underhill Moore, Herman Oliphant, and Warren Seavey, many of whom were associated with Yale Law School. As Keith Bybee argues, “legal realism has exposed the role of politics in judicial decision-making, thus challenging conventional efforts to anchor the judiciary on a firm and impartial basis.”  Contemporary jurists working in the tradition of law and society have broadened the foundations of legal realism to postulate what has been called the new legal realism. “American legal realism and the empirical social sciences are a refreshing and insightful analysis of the origins, flourishing, and decline of `legal realism.` His book succeeds admirably not only in broadening our understanding of legal realism, but also in shedding light on the cultural development of the law professor`s profession and the course of academic legal thought in the United States of the twentieth century. Schlegel has written a meticulously researched, astute, and provocative book that contributes immeasurablely to our understanding of legal realism and the culture of American jurisprudence.
It was to become a cornerstone of subsequent discussions on American legal thought and twentieth-century education. Many critics have argued that realists have exaggerated the extent to which the law is “interspersed” with loopholes, contradictions, etc.  The fact that most legal questions contain simple, clear answers that no lawyer or judge would challenge is difficult to reconcile with the realists` strong claims about the pervasive legal “vagueness.” Other critics, such as Ronald Dworkin and Lon Fuller, have criticized right-wing realists for their attempt to clearly separate law and morality.   American realist jurists believe that there is more to decide than the “mechanical” application of known legal principles to undisputed factual conclusions in accordance with the arguments of legal formalism. Some realists believe that one can never be sure that the facts and law identified in the judge`s reasons were the real reasons for the verdict, while other realists accept that one can often rely on a judge`s reasons, but not all the time. Realists believe that the legal principles that legal formalism treats as non-controversial actually hide controversial political and moral choices.