There is a plethora of adjectives in English, derived from ancient Greek, which end in both “-ic” but also “-ical.” There is no change in meaning between the two suffixes. These words often involve science, mathematics, pedagogy, or the arts (and have been adapted to English as a reflection of Greek intellectual traditions). Here is an incomplete list:
magic/al, anatomic/al, geographic/al, comic/al, geometric/al, metric/al, astronomic/al, artistic/al, athletic/al, dramatic/al, linguistic/al, syntactic/al, phonetic/al, majestic/al, tragic/al, linguistic/al, theatric/al, dialectic/al, mathmatic/al, symetric/al, cartographic/al, theoretic/al, biologic/al, diametric/al, hypothetic/al.
A number of the –icals in this family have fallen out of popular usage and become archaic: fantastical, academical (ask Thomas Jefferson), catholical, democratical, (ironically…) archaical, (also ironically…) ironical, domestical, emphatical, mosaical, energetical, neurotical, pathetical, and publical.
Kicker Number 1: The adverbial forms of these archaic family members, still in common usage, have retained their –icals: academically, democratically, archaically, ironically, domestically, emphatically, energetically, neurotically, pathetically, publically, BUT NOT publicly.
Kicker number 2: ‘Historic’ and ‘historical’ often (but not always) have TWO different connotative meanings. Based on a prelimary google search, ‘historic’ often means important (as in, “an historic occasion”), whereas often ‘historical’ takes on a less serious implication (as in, ‘historical evidence’).
Bottom line: English is not fair.