This presentation examines various difficulties that beginning programmers sometimes encounter when attempting to debug software. Unfortunately, some beginning programmers make repetitive guesses in an attempt to solve a problem. First, this presentation examines how to break this cycle of guessing. Second, although there are a number of definitions of critical thinking, this presentation will examine one of the original ones proposed by John Dewey. Next, it looks at how critical thinking can be employed when walking through code to debug a logic error. Lastly, it offers some suggestions and provides some closing thoughts. The audience for this presentation is students, tutors, lab assistants, teaching assistants, and instructors, especially ones new to their roles. For those who may already possess good debugging skills, it might help articulate what they have already been practicing.