For a slightly different and more in-depth treatment of the basic concepts of logic see the logic chapter of Jonathan Weisberg’s open source textbook on probability and statistics, Odds & Ends.
Wireless Philosophy is a well-produced series of short videos on a great many topics in philosophy. Their playlist on Logic and Critical Thinking is a great resource for exploring logical thinking in all of its complexity, 5 or 6 minutes at a time.
Critical Thinking Web: A great site with over 100 free tutorials on many aspects of logic and critical thinking. A nice way to hone your logical thinking skills.
Deductive and Inductive Arguments: An in depth look at the subject at the Internet Encyclopedia of Philosophy.
Abduction: A close look at the logic of scientific explanation. Gets technical, but the introduction is accessible.
The Irrationality of Politics: Michael Huemer is a professor of philosophy at the University of Colorado. This TED Talk by him addresses the question of why we are so irrational when it comes to politics.
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