For instance, our knowledge of a walrus Is different from our knowledge of a triangle because a walrus differs from a triangle; and the knowledge a stonecutter has of a stone differs from the knowledge a geologist has of the same stone because each considers a different aspects of the stone. The things a science considers?that is, the things as they are in themselves together with all their attributes?constitute its material object. Many sciences can have the same material object (or general subject matter); but each distinct science insiders a distinct and special aspect of its material object.
This special aspect is called the formal object of the science.
We shall now state the material objects of logic, then the formal object, and then give the actual definition of logic in terms of Its formal object. A. The Material Object The material object of logic includes all things without exception. It Includes all that the human mind can know, all that we can grasp by simple apprehension, judgment, and reasoning. Consequently, the material object of logic includes the
In its formal object logic differs from all the other sciences. Metaphysics, the philosophy of God, the philosophy of human nature, and all the purely speculative sciences study real beings?God, man, the world, and so on?as they exist (or can exist) independently of our thinking of them.
C. The Definition Itself In terms of its formal object, logic is defined as the science of the attributes and relationships that things have as they exist in the mind and get as a result of being known.
In other words, it is the science of the mental representation of real beings, a science not directly of things but of certain aspects of our knowledge of things, a science of beings of reason. Briefly, logic is the science of second intentions. Both of the definitions we have given are too broad if they are taken by themselves.
The first definition is too broad for two reasons. In the first place, unless we arbitrarily restrict the meaning of “thinking”, there are kinds of thinking that do not fall within the scope of logic; for instance, reverie, day dreaming, and the chance association ideas.
In the second place, logic cannot lay down rules for the validity of material sequence or for the understanding of first principles, and so on. Logic is the science of those beings of reason that the mind must consider in formulating the laws of correct thinking, and the art that applies these laws. Synopsis Logic is the science which at least indirectly considers all beings (material object). It considers them according to the attributes and relationships they have as they exist in the mind and get as a result of being (formal object).