Courses are more appealing to me than books. Although the best books will always win out over mediocre courses, there are a few reasons why a great course can make an impression.

For starters, courses usually cover fundamental concepts. Most books make an effort to be unique. But a lot of what's important to know is actually rather old.

Courses are more evenly distributed. A lecturer delivering a fundamental course will attempt to explain the majority of the important points of view. A popular book by the same professor, on the other hand, could be utterly one-sided as they aim to make the strongest argument for their point of view. Polemical works can be helpful, but they can also be deceiving if you mistake a controversial subject for a black-and-white situation.

I enjoy watching classes as well. Reading is beneficial. However, listening and watching are also important. You'll probably learn more than if you just stick to text if you do all three.

Here are my top recommendations for free online courses to watch.

1. Justice — Michael (Harvard)

Honestly, just to see one of the best professors of all time, this course is worth watching. Michael teaches moral philosophy, which isn't usually the most exciting subject. Despite this, the lectures are engaging, with students debating real-life situations to explain philosophical principles.

What strikes me the most is Michael's ability to convey esoteric concepts to his pupils through Socratic dialogue, using their emotions to exemplify the philosophical principles he wishes to convey. This is one of Harvard's most popular classes among incoming freshmen for a reason. You no longer need to be a Harvard student to take it.

2. Physics — Walter Lewin (MIT)

During the MIT Challenge, I followed Walter Lewin's physics lectures (both classical and electromagnetic). They're among the best online classes I've ever taken. Lewin uses exciting experiments to explain complex concepts about how the world works. He can also draw dotted lines very well.

Unfortunately, there was a bit of a scandal on MIT's open platform, and as a result, MIT dropped Lewin's name off the course. As a result, finding the lectures online is more difficult than it used to be. However, since nothing is ever truly deleted from the internet, I believe they are still worthwhile to watch if you want to learn physics.

3. Learning How to Learn — Terrence Sejnowski and Barbara Oakley (UCSD)

This is Coursera's most popular course, and it's also taught by my buddy Barbara Oakley. The course is fun and easy to follow, and it uses neuroscience and psychology to demonstrate how to study more effectively.

I have to admit, I was a little worried when this course first came out because my income is largely dependent on my own, paid learning course. But, as I've grown to know, learning better is a really vast subject, and there will always be more to teach (and learn). Regardless, I think this course is a great resource!

4. Machine Learning — Andrew NG (Stanford)

With NG resigning his Stanford teaching post to begin Coursera, this course was the catalyst for the MOOC explosion. This course has evolved over time, starting as recorded lectures from a real Stanford class, then as a condensed MOOC, and finally as a full-fledged machine learning educational platform.

Because I prefer to embed YouTube, I've linked to the original Stanford class. The Coursera version is also a little hazy whether, it is truly free, or if there is a modest fee. However, because it is more recent, you might prefer the MOOC version here.

5. Quantum Mechanics — Richard Feynman

Richard Feynman is my intellectual hero of all time. He does a fantastic job of explaining quantum physics without using any math in this video. It would have seemed impossible to me, yet Feynman manages to pull it off. (Not to mention barefoot!)

While I enjoyed Allan Adams' MIT quantum physics course, the math requirements are somewhat demanding. I didn't include it since the number of people who have both the math and physics qualifications but didn't study quantum mechanics in their undergraduate education is likely to be small. (However, even if you don't know calculus, the first lesson of the class is math-free and really well done, so I recommend it.)