Court is concerned with Legal relevancy and not logical relevancy - Explanation.

 The word relevancy means connection of events as cause and effect. In ordinary parlance one fact is relevant to other when those two are closely connected and for the purpose of proper understanding of one of those two facts other is also required to be referred. Relevance therefore is based purely on logic.

 But Indian Evidence Act, 1872  has assigned a completely different meaning to the word 'Relevant'. The word relevant is mentioned in Section 3 that one fact is said to be relevant to another when it is connected with another in any of the ways referred to in the provisions relating to relevancy of facts in Sections 5 to 55 dealing with the Relevancy Chapter of the Evidence Act.

                            

There are two types of relevancy (1) Logical relevancy and (2) legal relevancy.

A fact is said to be logically relevant when by virtue of the application of our logic it appears to us that one fact has a bearing on another fact. But facts, which are logically relevant, are not provable.

For example, where a husband confesses to his wife that he has committed a murder, the wife is prohibited from giving evidence of this fact under Section 122 of the Evidence Act. Although evidence of this fact is logically relevant but it cannot be proved.

A fact is said to be legally relevant when it is expressly declare as relevant  under any of the provisions of Sections 5 to 55. 

For example, A is tried for the murder of B by administering poison. The fact is that A was to inherit the property of B, provides the motive which is relevant under Section 8 of the Evidence Act. The fact that A had procured similar poison from druggist shop shows that A has made preparation for administering poison, which preparation is again relevant under Section 8. The fact that A subsequently made a confession of administering poison which confession is relevant under Section 24. the fact that B shortly before his death made a dying declaration holding A responsible is relevant and provable under Section 32(1). The fact that a medical expert who conducted the postmortem has given his expert opinion that the death was caused by administering a particular poison is relevant under Section 45, All these facts are legally relevant as they are expressly declared as relevant under the Relevancy chapter. 

So under Section 5 the intention is clear that evidence may be given in any suit or proceeding of the existence or non-existence of every fact in issue and of such other fact as are declared to be relevant and of no other. Because every fact that is legally relevant is also logically relevant but every logically relevant fact may not be necessarily legally relevant. Therefore in deciding the fact to be relevant, the court must ask himself under what provisions of the relevancy chapter a particular fact which is sought to be proved is relevant. Then only he must admit such evidence.