Deductions is an educational software designed to help students learn proofs in formal logic. Deductions is intended to be used by students and instructors of college-level logic courses in philosophy, computer science and mathematics.

Deductions gives immediate feedback at each stage of a proof, provides hints about how to complete proofs, and comes with a set of video tutorials that explain and review several challenging concepts in logic.

Deductions aims to solve the three problems that make proofs the most difficult component of formal logic courses: not knowing whether rules are applied correctly, getting stuck in the middle of a proof, and uncertainty about the rules and strategies.

Deductions addresses these issues by flagging errors, including a hint engine to make suggestions about how to complete a proof, and having multimedia tutorials to help students through complex rules.

Here are some key features of "Deductions":

· Flagging Errors - Deductions flags errors in proofs as soon as they occur. This is important, because when students are first learning proofs, they are often not sure how to apply certain rules, and frequently end up practising mistakes. By flagging errors, Deductions prevents students from learning the wrong rules.
· Hint Engine - Deductions provides hints about how to complete proofs. A common frustration of students is that they get stuck in the middle of a proof. Deductions has a hints feature which looks at the proof the student is working on, and suggests how to make progress.
· Multimedia Tutorials - Deductions comes with a set of multimedia tutorials. There are so many rules for constructing proofs that it often difficult for students to keep all the details straight. Deductions comes with a set of video tutorials, divided into two groups: how to use Deductions to learn logic, and how to use the logic rules.
· Flexibility - Deductions is designed to work with many different logic systems and textbooks. Both standard and alternative symbols are included, as well as rules that may be turned on and off individually.
· Modern Design - Deductions provides a modern interface. As a new entry into a field that has not seen many updates in recent years (many logic programs are written for DOS, Windows 9x, or are rudimentary Java applets), Deductions is designed and written for a modern operating system (Mac OS X). Deductions leverages the technologies of Mac OS X to provide a clean user interface, drag-and-drop support, and a comprehensive help system.
· More Efficient than Paper - Deductions takes care of the editing details. When working on paper, especially in large proofs, proofs must be reworked to add or remove lines, existing justifications must be renumbered, and so on. These details are necessary for the proof to work, but have little to do with learning or understanding proofs. Deductions takes care of these housekeeping tasks by automatically adjusting proofs when lines are added, removed or moved.

Limitations:

· Only some rules are enabled.

What's New in This Release: [ read full changelog ]

· Sees the addition of 45 new rules and aliases, to bring the total number of rules supported to 85 (!), with each rule being able to be turned on and off individually.

Expanded the number of textbooks supported “out of the box” to ten:
· The Logic Book (Bergmann/Moor/Nelson, 2008)
· A Serious Introduction to Mathematical Logic (Roy, 2009) (Free online)
· A Modern Formal Logic Primer (Teller, 1989) (Free online)
· Logics by (Nolt, 1996)
· Symbolic Logic by (Jacquette, 2000)
· A Concise Introduction to Logic (Hurley, 2008)
· Introduction to Logic (Copi/Cohin, 2008)
· Logic and Philosophy (Hausman/Tidman/Kahane, 2009)
· The Power of Logic (Howard-Snyder/Snyder/Wasserman, 2008)
· Modern Logic (Forbes, 1994)

· Fuzzy string-matching has also been implemented when citing rules, to make it easier to enter justifications.
· Documentation has been updated across-the-board to reflect these major changes.