what will motivate the humans to porsuit knowledge if they didn't feel any thing?
I suspect that completely non-emotional human beings might have less desire to pursue knowledge than those who possess emotions. Desire, after all, can itself be seen as a kind of emotion, and it is especially emotion if it seen as, for instance, a desire for fame, a desire for money, a desire for immortality, a desire for victory in competition with others, a desire to do good by helping others, etc.
I think there is something in our brains that makes us pursue knowledge, some sort of built-in reward that gives us satisfaction when we learn something or solve a problem. Whether that is an emotional or intellectual satisfaction is difficult to say, and in fact, even those effects that we call "emotion" are the consequence of actions among neurons in our brains. I think that the more we learn about the human brain, the more we will come to see that thought and feeling are a false dichotomy. It all works together, and we have evolved to need both, together, to survive in the world.
I must say that not having emotions would reduce one's pursuit of knowledge. I think that people who are emotional about something tend to try harder to succeed. As a teacher, I see students who are not emotional about knowledge. They are simply happy (for lack of a better word) to sit in class because they are required to by law. Then there are the students who are passionate about school. These are the students, whose love for a subject, which will go to college and pursue the knowledge they crave.
I don't think that emotions cause us to pursue knowledge. Therefore, I think that it is likely that we would be farther ahead in these ways if we did not have emotions. Because we have emotions, we spent a lot of time pursuing things like love and happiness. If we did not spend our time in this way, we would presumably have more time for things like science and technology.