Prediction and Entropy of Printed English
"A new method of estimating the entropy and redundancy of a language is described. This method exploits the knowledge of the language statistics possessed by those who speak the language, and depends on experimental results in prediction of the next letter when the preceding text is known. Results of experiments in prediction are given, and some properties of an ideal predictor are developed."Bell Systems Technical Journal 30 pp. 50-64
Computing machinery and intelligence
An excellent place to start. In this article, Turing not only proposes the Imitation Game in its original form, but addresses nine different arguments against AI, including Goedel's theorem and consciousness. Several recent arguments against AI are variations on the ones Turing enumerates. 'I propose to consider the question, "Can machines think?" This should begin with definitions of the meaning of the terms "machine" and "think." The definitions might be framed so as to reflect so far as possible the normal use of the words, but this attitude is dangerous....The new form of the problem can be described in terms of a game which we call the "imitation game."' I.—COMPUTING MACHINERY AND INTELLIGENCE. Mind 59, p. 433-460 (PDF from Oxford University Press).