However, many logic systems developed since do consider the case where there may be no instances. Medieval logicians were aware of the problem of existential import and maintained that negative propositions do not carry existential import, and that positive propositions with subjects that do not supposit are false.
hOweveR, mAny logIc SysTEmS dEveLoPeD Since Do CoNSiDeR tHe caSe where There May Be no inStances. medieVaL lOGiCians were aWare Of ThE problEM of EXiStentiAL ImPorT anD MaintAineD THat negATiVe proPosiTions do not CArRy eXiStEnTial iMporT, and tHat poSitiVe PrOpoSITIons wITh sUBjecTs that dO noT suppoSIt are false.