w esen . ▁ ▁H ahn emann ▁and ▁the ▁special ▁theory ▁of ▁disease ▁ ▁At ▁the ▁same ▁time ▁that ▁Rö sch la ub ▁emb ark ed ▁on ▁his ▁quest ▁for ▁a ▁true ▁science ▁of ▁life ▁and ▁health , ▁a ▁compat ri ot , ▁Dr . ▁Samuel ▁H ahn emann , ▁who ▁had ▁quit ▁his ▁medical ▁practice ▁earlier ▁in ▁protest ▁against ▁the ▁lack ▁of ▁science ▁and ▁effic acy ▁of ▁the ▁Old ▁School ▁and ▁the ▁empty ▁‘ met as ch emat isms ’ ▁of ▁the ▁academic ▁‘ do ctors ’ , ▁had ▁also ▁begun ▁a ▁similar ▁quest ▁for ▁a ▁true ▁system ▁of ▁medicine . ▁H ahn emann ' s ▁ess ay ▁of ▁ 1 7 9 6 ▁and ▁subsequent ▁writ ings , ▁all ▁part ▁of ▁an ▁extended ▁Organ on ▁der ▁Heil k unst , ▁laid ▁down ▁the ▁basic ▁foundation ▁for ▁a ▁distinction ▁between ▁the ▁sust ent ive ▁( L eb enser halt ung sk raft ) ▁[ A ph or ism ▁ 6 3 , ▁ 2 0 5 ▁fn ., ▁ 2 6 2 ) ▁and ▁gener ative ▁( Er zeug ung sk raft ) ▁[ A ph or ism ▁ 2 1 - 2 2 ] ▁sides ▁of ▁the ▁living ▁principle , ▁between ▁phys ic , ▁operating ▁under ▁the ▁natural ▁he aling ▁law ▁of ▁oppos ites ▁( contr aria ▁contr arius ), ▁and ▁medicine ▁proper , ▁operating ▁under ▁the ▁natural ▁cur ative ▁law ▁of ▁sim il ars ▁( sim ilia ▁sim ilib us ), ▁and ▁between ▁disease , ▁a ▁dynam ica ▁imp ing