Consider the following premises. For all x_18, if x_18 were an artist, then x_18 is playing a game. For all x_18, x_18 will drink water. For all x_18, x_18 will play a game if and only if x_18 is a scientist. There is at least one x_18 for which x_18 is an artist. Can we infer the following from them? If we can, name the inference rule being used: For all x_18, x_18 will not play a game.
 From the fact that for all x_18, x_18 will play a game if and only if x_18 is a scientist we can infer that for all x_18, if x_18 were a scientist, then x_18 is playing a game via universal biconditional elimination. From the fact that there is at least one x_18 for which x_18 is an artist we can infer that there is at least one x_18 for which x_18 is an artist or x_18 is a scientist via existential addition. From the fact that for all x_18, if x_18 were an artist, then x_18 is playing a game, that for all x_18, if x_18 were a scientist, then x_18 is playing a game, and that there is at least one x_18 for which x_18 is an artist or x_18 is a scientist we can infer that there is at least one x_18 for which x_18 will play a game via existential disjunction elimination. From the fact that there is at least one x_18 for which x_18 will play a game, and that for all x_18, x_18 will drink water we can infer that there is at least one x_18 for which x_18 will play a game and x_18 will drink water via existential conjunction. Finally, from the fact that there is at least one x_18 for which x_18 will play a game and x_18 will drink water we can infer that there is at least one x_18 for which x_18 will play a game via existential simplification, which contradicts that For all x_18, x_18 will not play a game. Therefore, the answer is no.