The argument is structured as a basic modus tollens : if " creation " contains many defects, then design is not a plausible theory for the origin of our existence.
12.
The argument is in the form of a modus tollens : If P then Q; but Q is implausible ( or " queer " ), so P is implausible.
13.
They accept the possibility of motion and apply modus tollens ( contrapositive ) to Zeno's argument to reach the conclusion that either motion is not a supertask or not all supertasks are impossible.
14.
Modus tollens is an admissible rule of intuitionistic logic : it's the converse, if ~ q?! ~ p then p?! q which the intuitionists reject ( and adding this rule to intuitiontistic logic gives classical logic ).
15.
Takes in the index " k " of an inference rule ( such as Modus tollens, Modus ponens ), and attempts to apply it to the two previously proved theorems " m " and " n ".
16.
This mode of argument bears the same relation to proof by mathematical induction that " If not B then not A " ( the style of " modus tollens " ) bears to " If A then B " ( the style of " modus ponens " ).
17.
Note that the goals always match the affirmed versions of the consequents of implications ( and not the negated versions as in modus tollens ) and even then, their antecedents are then considered as the new goals ( and not the conclusions as in affirming the consequent ) which ultimately must match known facts ( usually defined as consequents whose antecedents are always true ); thus, the inference rule which is used is modus ponens.
