What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all x_8, x_8 will write a letter. For all x_8, x_8 is not a carpenter. For all x_8, if x_8 writes a letter, then x_8 is a carpenter. For all x_8, x_8 is an astronaut.
Since the premises are contradictory, we can infer anything from them.