 Formal logic employs artificial abstract languages generally understood to address particular types of inference. Formal symbolism is also used to interpret arguments from natural language so as to assess the strength of an argument’s inference, in particular, whether the argument has deductive validity. So, the argument, “It is icy outside and therefore I will not travel today” might fail to be translatable into a deductively valid form, although people easily recognize its good reasoning. (“Missing premises” might be added to make the argument deductive but that requires more than formal interpretation.)