Deductive and non-deductive inferences play different roles in knowledge. But how does one characterize and classify them and their role? This is a basic logic task. Peirce even says that “the chief business of the logician is to classify arguments.”1 What can be termed as the standard classification of inferences is stated by Hintikka and Sandu as follows: “Inferences can be either deductive, that is, necessarily truth preserving, or ampliative, that is, not necessarily truth preserving.”