the distinction and opposition of possible, actual and necessary matter, which has been introduced into Logic, is a doctrine wholly extraneous to this science. Welton In the 19th century, the Aristotelian laws of thoughts, as well as sometimes the Leibnizian laws of thought, were standard material in logic textbooks, and J. Welton described them in this way: Russell (1903–1927) The sequel to Bertrand Russell's 1903 "The Principles of Mathematics" became the three-volume work named Principia Mathematica (hereafter PM), written jointly with Alfred North Whitehead. Immediately after he and Whitehead published PM he wrote his 1912 "The Problems of Philosophy". His "Problems" reflects "the central ideas of Russell's logic". The Principles of Mathematics (1903) In his 1903 "Principles" Russell defines Symbolic or Formal Logic (he uses the terms synonymously) as "the study of the various general types of deduction" (Russell 1903:11). He asserts that "Symbolic Logic is essentially concerned with inference in general" (Russell 1903:12) and with a footnote indicates that he does not distinguish between inference and deduction; moreover he considers induction "to be either disguised deduction or a mere method of making plausible guesses" (Russell 1903:11). This opinion will change by 1912, when he deems his "principle of induction" to be par with the various "logical principles" that include the "Laws of Thought". In his Part I "The Indefinables of Mathematics" Chapter II "Symbolic Logic" Part A "The Propositional Calculus" Russell reduces deduction ("propositional calculus") to 2 "indefinables" and 10 axioms: "17. We require, then, in the propositional calculus, no indefinable except the two kinds of implication [simple aka "material" and "formal"]-- remembering, however, that formal implication is a complex notion, whose analysis remains to be undertaken. As regards our two indefinables, we require certain indemonstrable propositions, which hitherto I have not succeeded in reducing to less ten (Russell 1903:15). From these he claims to be able to derive the law of excluded middle and the law of contradiction but does not exhibit his derivations (Russell 1903:17). Subsequently, he and Whitehead honed these "primitive principles" and axioms into the nine found in PM, and here Russell actually exhibits these two derivations at ❋1.71 and ❋3.24, respectively. The Problems of Philosophy (1912) By 1912 Russell in his "Problems" pays close attention to "induction" (inductive reasoning) as well as "deduction" (inference), both of which represent just two examples of "self-evident logical principles" that include the "Laws of Thought." Induction principle: Russell