11. These inference engines support forward reasoning or backward reasoning to infer conclusions via modus ponens . 12. It isn't modus ponens . 13. From these, we can obtain B by an application of the standard deduction rule modus ponens . 14. :Well, I changed my approach and did a second transitivity instead of a modus ponens . 15. Modus ponens is closely related to another valid form of argument, " modus tollens ".16. Hypothetical syllogism is closely related to modus ponens and sometimes thought of as " double modus ponens ." 17. Hypothetical syllogism is closely related to modus ponens and sometimes thought of as " double modus ponens ." 18. X and " modus ponens " implies X and subsequently Y ( as in above proof ). 19. This rule is equivalent to the rule of inference known as modus ponens , except it is going backwards. 20. Applying modus ponens , we get that " A " is a theorem of the extended system.