The parties put forward their claims and defenses in the case. These claims and defenses are also based on a number of lived events. If these cases are in contention between the parties, it becomes necessary to prove this. The parties must prove the facts they claim and put forward so that it is understood that they actually exist and the judge can make an opinion and decide accordingly.

Evidence is classified as conclusive evidence and discretionary evidence. Definitive evidences are those that are determined by the law and in which the discretion of the judge has disappeared even though it is found. Although certain evidence is foreseen, the judge will not be able to examine other evidence. If a fact is proven with definitive evidence, the judge has to accept the truth of this fact and make a decision accordingly. Discretionary evidence is not binding on the judge. Evidence at the discretion of the judge. These are the witness, the expert and the discovery.

A witness is a person who conveys information that the incident alleged in the case occurred in the past. Third parties who are not parties to the case will be able to testify. Although the judge will listen to these witnesses in court, it is at his own discretion whether to take the statements of these witnesses as a basis for his judgment.

If no witnesses are presented in court, it will be difficult to prove the facts in dispute. Although it is discretionary evidence, witness and proof can often play a decisive role. While the formation of an opinion in the judge is important for the future of the case, the fact that the witness evidence, which is one of the most used evidence, is not used in the case may cause loss of rights.

Evidence in business proceedings; employee personal file, minutes, warning, workplace payrolls, witnesses, camera records, employment contract, entry and exit records, etc. can be listed as The importance of witness evidence plays an important role in reemployment cases. Because the people selected as witnesses are selected from the people working in the same place under the same working conditions, and the realization of the proof is important for the judge to form an opinion. In a decision of the Court of Cassation, it is okay for a person who has enmity with the employer to testify in an employment lawsuit in favor of another employee, but this alone cannot be taken as a basis for the acceptance of the case, which shows the importance of witness evidence in these cases.