What grounds the particle contrast in “for it / against it”?

Introduction to ʿIlm al-Badīʿ: Ṭibāq and Muqābalah

• Kasabat and iktasabat are the same particles
• Li- and ʿalā are always logical contradictories
• Neither side refers to an act
• The favorable and burden-bearing senses conveyed by li- and ʿalā