Common law is systems of law whose particular difference is the doctrine of antecedent, or stare decisis (Latin for "to stand by decisions"). Alongside this "judge-made law", common law systems constantly have governments who pass new laws and statutes. But these are not put into a codified structure. Common law arrive from England and was inherited by almost every country that once pertained to the British Empire, with the exceptions of Malta, Scotland, the U.S. state of Louisiana and the Canadian province of Quebec.
In common law systems, the law is produced and/or polished by judges: a resolution in the case currently pending depends on decisions in preceding cases and alters the law to be applied in future cases. When there is no authoritative statement of the law, common law judges have the power and obligation to "make" law by creating antecedent. The body of antecedent is called "common law" and it connects future decisions. In future cases, when parties differ on what the law is, an "ideal" common law court looks to past precedent decisions of important courts.
If a similar disagreement has been determined in the past, the court is bound to pursue the reasoning used in the prior conclusion (this principle is known as stare decisis). However, the court finds that the current disagreement is basically different from all preceding cases, it will decide as a "matter of first impression." Subsequently, the new resolution becomes antecedent, and will combine future courts under the principle of stare decisis.
In execute, common law systems are significantly more difficult than the "ideal" system explained above. The decisions of a court are binding only in a special jurisdiction, and even within a given jurisdiction, some courts have more authority than others. For example, in most jurisdictions, decisions by appellate courts are binding on lower courts in the same jurisdiction and on future decisions of the same appellate court, but decisions of non-appellate courts are only non-binding influential power.
Connections between constitutional law, common law, legislative law and regulatory law also give increase to substantial difficulty. However stare decisis, the principle that similar cases should be decided according to similar regulations, falsehood at the heart of all common law systems.
Currently, Common law is practice in Ireland, United Kingdom (excepting Scotland), Australia, India, South Africa, Canada (excepting Quebec), Hong Kong and the United States (excepting Louisiana) and many other places. In addition to these countries, some others have adjusted the common law system into a mixed system. For example, Pakistan and Nigeria operate largely on a common law system, but incorporate religious law.