I will try my best to recreate his lecture in this post. Before answering the question in title directly, he also answered few other questions too.
How to gain knowledge?
Lets assume gaining knowledge is analogous to the process of gaining muscles i.e. body building. Lets try and see if the following approach works.
We go to gym everyday for one hour, watch the instructor doing exercise for 6 months continuously. Do our muscles grow? NO. Had we gone to gym, started lifting dumbbell, for one hour everyday and continued the same for a period of six months, we would have ended up growing muscles. But how, why? When you start using dumbbells, you suffer pain initially, in order to endure the pain you signal your genetics(body) to add more muscles to your body. Thus your muscles grow to survive, to endure the pain. But adding muscles doesn’t happen immediately, it takes time, it is a slow process.
Similarly when you just attend a lecture and keep watching what your professor is doing, you don’t gain knowledge. It is when you try to learn, read a book, practice, fail to understand, you signal your brain to gain knowledge to understand the subject better. And again, gaining knowledge takes time like your muscle take time to grow.
How to read books?
If you know that carbon filament was one of the key element in the success of first commercial and practical light bulb, your IQ is not equal to that of Edison. Why? Because Edison tried & tested lot of other materials before carbon filament and failed. He realised, reasoned that they were not suited for this purpose. This is the most important knowledge (failures and reasoning) we all lack of. Books are just a list of success stories. An author cannot recreate the entire history of the invention which dates 1000's of year back or more than that.
Therefore try to simulate what could have been the failures that would have led to this invention, you will enjoy & appreciate the invention better.
Why to gain knowledge?
We have not yet answered the question in the title. Have we? We will soon!
Lets us consider an example. Two animals are walking down a path. One of them falls into a quick sand, what would another animal do? We cannot say anything deterministically, however lets assume that the animal wants to help other animal with all its capability. It still cannot, because it doesn’t have enough knowledge to help the other animal. Lets us consider a different scenario, Earth and Mars are orbiting around Sun and an asteroid is in the orbit of Mars. Can Mars save itself from the danger? Probably no. But if somehow Mars could signal Earth that it needs help, collective knowledge of all the people in the earth can pitch in and help. Thus,
“Service that we can offer to others is a function of Knowledge that we possess.”
But why do we need to service or help others? Lets us assume we are not interested. So we are still trying to find a reason for the question, why to gain knowledge?
We all enjoy cricket. Why? Because we know team scoring high wins, when ball is hit beyond a line it is a boundary i.e. we have enough knowledge to understand what is happening. So we enjoy! Let us consider a more entertaining example, when you watch a movie in a language that you understand and another in a language that you don’t understand. Which you would have enjoyed more? Thus,
“Enjoyment is a function of Knowledge that we possess.”
Moreover in order to enjoy a movie you need very little knowledge. Hence you enjoy movies very easily. However to enjoy your lectures you need more knowledge. If you are able to push yourselves i.e. signal the brain to gain more knowledge, you will start enjoying lectures like a movie.
So are we convinced that we need to gain knowledge? Continue, even if you are.
Do we really need to know how to solve Linear Differential Equations (LDE)? Leave aside LDE’s do we need to know how to perform a multiplication. Answer is NO. Why? There are lot of machines that can do this for us in a single click of the button. These were really needed when machines never existed. Now they are not actually needed. Then why to gain knowledge?
Humans have captured only finite knowledge till now. What we need to worry about is gaining unknown knowledge. If you had only 1 movie to watch in your entire lifetime you would have been bored after watching it “n” times. Because you know the climax and there is no surprise when you watch the next time. You enjoy more when something unexpected/unknown happens. Gaining unknown knowledge is like watching a movie without knowing climax, which you would enjoy and appreciate more. Life is very interesting, enjoyable as it is very much unexpected and unknown things unfold every moment.
If knowledge becomes finite we would end up bored. Fortunately, it is proved that knowledge is infinite and we will never get bored.
“Brain is a unique thing that is well designed to gain knowledge, better than any other task.”
Start gaining knowledge, you will enjoy life better than now!
Once again, I would like to credit Dr. Kannan Srinathan for such an inspiring talk on Why to gain knowledge? during his Data Structures lecture.