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1856 A. De Morgan in Trans. Cambr. Philos. Soc. 9 83 I think it reasonably probable that the advance of symbolic logic will lead to a calculus of opposite relations, for mere inference, as general as that of + and − in algebra.

1881 Venn (title) Symbolic Logic.

1903 B. Russell Princ. Math. ii. 10 Symbolic or Formal Logic—I shall use these terms as synonyms—is the study of the various general types of deduction. The word symbolic designates the subject by an accidental characteristic, for the employment of mathematical symbols, here as elsewhere, is merely a theoretically irrelevant convenience.

1903 B. Russell Princ. Math. vi. 74 By symbolic logicians..this will be felt as a reactionary view.

1933 C. A. Mace Princ. Logic iv. 64 The fact that symbolic logicians have not generally recognized this form compels us to introduce a symbol that is not in common use.

1941 O. Helmer tr. A. Tarski Introd. Logic ii. 18 Logic..has undergone a complete transformation with the effect of assuming a character similar to that of the mathematical disciplines; in this new form it is known as mathematical or deductive or symbolic logic.

1958 Times Lit. Suppl. 19 Dec. 729/3 Professor Sparshott quotes the dying symbolic logician—‘complete rigour at last!’

1968 Brit. Med. Bull. 24 239/2 The final study to be reviewed concerns diagnosis by the computer using a combination of symbolic logic..and similarity coefficients.

1973 Sci. Amer. Apr. 101/3 First Frege, then Peano and finally Russell turned to symbolic logic as a potential source of the fundamental notions necessary for a theory of natural number.