However, there are two exceptions to this rule: expert evidence and non-expert opinion given by laymen which people in their daily lives reach without conscious ratiocination.
[2] The main rationale for such a rule is that the admission of opinion evidence would not assist, or might even mislead, the court and in particular the jury.
Moreover, admission of such evidence would usurp the functions of the jury, which alone should be the tribunal of fact and draw its own inferences.
Court me take help of DNA expert in order to ascertain the parentage of any child or person.
An expert witness is a witness, who by virtue of education, training, skill, or experience, is believed to have expertise and specialised knowledge in a particular subject beyond that of the average person, sufficient that others may officially and legally rely upon the witness's specialized (scientific, technical or other) opinion about an evidence or fact issue within the scope of his expertise, referred to as the expert opinion, as an assistance to the fact-finder.