What do you understand by fact? Explain with illustration “Relevant Fact” and “fact in Issue”

Facts play important role in Evidence Law because all rights and liabilities depend upon facts and also originate from it. 

"Fact" – "Fact" means and includes-
 
(1) Anything, state of things, or relation of things, capable of being perceived by the sense;
 
(2) Any mental condition of which any person is conscious.

Rights and liabilities in judicial proceedings emerge out of fact. Section 3 of the Indian Evidence Act categories fact into - 

    1) Physical facts and 

    2) Psychological facts.  

A) Physical facts - It means and includes anything, state of a thing or relation of things, capable of being perceived by senses. In other words, all facts which are subject to perception by bodily senses are physical facts.  They are also called external facts. 

B) Psychological facts - those facts, which cannot be perceived by senses, are 'Psychological Facts' they are also known as internal facts. Examples- Intention (Mens Rea) knowledge, good faith, fraud, etc. 
Illustration 
1 That a man has a certain reputation is a fact 
2 That the building of A is in the west is a fact 

Fact in issue: 
Facts in issue are the matters which are in dispute or which form the subject of the decision in the suit. They are facts out of which some legal right, liability, or disability, involved in the inquiry, necessarily arises and upon which a decision must be arrived at. They are matters affirmed by one party and denied by the other. Thus, if A is accused of the murder of B, the facts in issue will be that A caused B’s death, that he intended to cause B’s death,

Relevant
One fact is said to be relevant to another when the one is connected with the other in any of the ways referred to in the provisions of this Act relating to the relevancy of facts.
Relevant can e interpreted in two ways, firstly it means connected and secondly, it means admissible. Relevancy means the connection of events as cause and effect. It has a certain degree of probative force. A fact becomes relevant only when it is connected with other facts in any of the ways referred to in this act relating to the relevancy of facts. In order to be a relevant fact, a fact should be connected with the facts in issue. A fact not so connected is not a relevant fact. When a fact is connected with other facts, it is logically relevant but it is legally relevant if the law declares it to be relevant. If the law does not declare it be relevant, it is not admissible as evidence.