DK Johnston, of the University of Victoria British Columbia, has written three iPhone apps for intro to logic courses. But you can use them however you like. Get them while they’re hot.
Construct syllogisms, test for validity, and display Venn diagrams.
For truth-functional logic. Check syntax, generate truth tables, test for validity and consistency, choose notation to match any textbook.
Construct derivations in the system SL of The Logic Book.
These will also work on the iPod Touch.
Tip 17: use them to judge the logic of the person to whom you’re not listening because you’re thumbing around on your iphone.