In Howell v. State, 157 Ga. App. 451 (278 S.E.2d 43) (1981) the Court discussed the purpose of the "substantial step" requirement: It is intended that the requirement of a substantial step will result in the imposition of attempt liability only in those instances in which some firmness of criminal purpose is shown. In addition to assuring firmness of purpose, the requirement of a substantial step will remove very remote preparatory acts from the ambit of attempt liability and the relatively stringent sanctions imposed for attempts. On the other hand, by broadening liability to the extent suggested, apprehension of dangerous persons will be facilitated and law enforcement officials and others will be able to stop the criminal effort at an earlier stage thereby minimizing the risk of substantive harm without providing immunity to the offender. Id. at 456 (4). Thus, the "substantial step" requirement is intended to: (1) ensure firmness of the defendant's criminal intent; (2) insulate from liability "very remote preparatory acts,"; (3) allow for apprehension of offenders at an early stage without providing immunity for their actions.