In the 1880s Peirce suggested that Boolean algebra could be used to design relay computers and that evolutionary processes and inductive processes are analogous. The first well-developed applications of logic to biology were McCulloch & Pitts's (1943) idealized neuron networks and von Neumann's self-reproducing automata. While these are interesting models, their fit to actual biological phenomena is rough.

How may the fit of logic to biology be made closer? Various ways are suggested: more detailed applications, the development of biology in the direction of automata theory, and by using formalisms that combine deduction with induction. Evolution is a statistical or inductive process, but genetic strings play a deductive role.

Formal languages are different from natural languages in rigor and precision, yet they give fair models of deduction, induction, and grammar. Other uses of language, such as the empirical, seem basically informal. Consider, however, a computer with appropriate input and output devices which interacts with its environment and communicates in a sophisticated language. It would understand empirical concepts and would verify empirical statements, and hence would model the empirical use of language.

The logical design and initial state of any computer, and a fortiori of this computer, can be expressed as a recursive formula of a formal language. Hence the empirical aspect of language is also formalizable.