TY - Front. Philos. China A1 - Liu Huajie T1 - Instability, Modus ponens and uncertainty of deduction Y1 - 2006-12-05 JF - Frontiers of Philosophy in China JO - Front. Philos. China SP - 658 EP - 674 VL - 1 IS - 4 UR - https://academic.hep.com.cn/fpc N1 - 10.1007/s11466-006-0030-7 ER -