Rule 102 - Purpose and construction(a) In general. - These rules shall be construed to secure fairness in administration, elimination of unjustifiable expense and delay, and promotion of growth and development of the law of evidence to the end that the truth may be ascertained and proceedings justly determined.(b) Subordinate divisions. - For the purpose of these rules only, the subordinate division of any rule which is labeled with a lower case letter shall be a subdivision.