We examine students' commonsense understanding of computer science concepts before they receive any formal instruction in the field. Specifically, we asked students on the first day of a CS1 class to describe in English how they would arrange a set of numbers in ascending, sorted order. We repeated the experiment with students in an introductory economics course, and again with a sub-population of the CS1 students after ten weeks of Java instruction.We found that a majority of beginning computing students could describe a coherent algorithm to correctly sort a list of numbers, while less than a third of general college students could do so. Many students gave versions of selection or insertion sort, but the most common algorithm treated numbers as strings and manipulated them digit by digit. Students who used iteration strongly preferred post-test loops. Finally, some aspects of student performance became worse after ten weeks of CS1 instruction.