Did C. S. Lewis write The Dark Tower?: An Examination of the Small-Sample Properties of the Thisted-Efron Tests of Authorship

John Rasp,Jeffrey R. Thompson

doi:10.17713/ajs.v38i2.262

Abstract

The Dark Tower is a fragment of a science fiction novel, attributed to C.S. Lewis and published posthumously. Shortly after its publication controversy arose, questioning the work’s provenance and authenticity. This controversy still continues. We apply and extend procedures developed by Thisted and Efron (1987) to investigate whether word usage in The Dark Tower is similar to that in Out of the Silent Planet and Perelandra, two worksof the same genre and period known to be by Lewis. We further examine the validity and limitations of these procedures in the case at hand. Our results show vocabulary usage in The Dark Tower differs from that predicted by the baseline Lewis works.

Highlights

Lewis wrote numerous works on a wide variety of topics, ranging from children’s stories to Christian apologetics to literary criticism. Among his books is a trilogy of science fiction novels: Out of the Silent Planet, Perelandra, and That Hideous Strength
We have observed that the TE procedures employed in this paper require t to be small enough to allow convergence – that is, a sample text much smaller than the baseline canon
This results in quite small sample sizes and with moderately low power for tests. This limits the usefulness of the TE procedures in resolving some authorship issues

Summary

Introduction

Lewis wrote numerous works on a wide variety of topics, ranging from children’s stories to Christian apologetics to literary criticism Among his books is a trilogy of science fiction novels: Out of the Silent Planet, Perelandra, and That Hideous Strength. This work was later extended (Thisted and Efron, 1987) to investigate whether Shakespeare wrote a newly discovered poem (the “Taylor poem,” after its discoverer) that had been attributed to him. These procedures have been used to investigate other authorship controversies as well.

Thisted and Efron Procedures

Implementation and Validity Issues

Results

Conclusions

A Computing the Thisted-Efron Slope Test