 All true propositions denote one and the same object, namely truth, and all false propositions denote one and the same object, namely falsehood. I consider truth and falsehood to be singular objects in the same sense as the number 2 or 4 is. … Ontologically, truth has its analogue in being, and falsehood, in non-being. The objects denoted by propositions are called logical values. Truth is the positive, and falsehood is the negative logical value. … Logic is the science of objects of a special kind, namely a science of logical values. (Łukasiewicz 1970: 90) 