A、Because we have made up our minds to do so. B、Because we want to fulfill our desire for knowledge. C、Because we want to enjoy

The sum total of our knowledge is very small compared to the size of our ignorance. Every advance on the frontier of knowledge opens up a great vista of the unknown. The scientist is not happy except when he finds something new．Science is an incomplete task just as life is incomplete. He can only be happy because he has the opportunity to continue the search. Fulfillment can never be there so long as knowledge is imperfect.
    The search for truth is not a peaceful occupation. The happiest people I have known have not been the men of great worldly achievements or wealth. They have been the simple people who are happily married, enjoying good health and good family life.
I do not think we search for the stars or moon because we make up our minds to do so, but because we can’t help ourselves. Imagination is not an attribute of happiness. A person can be very happy when he knows nothing.
    While it is true you can get happiness, peace and serenity from being at the lower end of the ladder, it is also true that you cannot enjoy the ecstasy of achievement. Success in the general sense of the term means the opportunity to experience and to realize to the maximum the forces that are within us.