We can invent as many theories we like, and any one of them can be made to fit the facts. But that theory is always preferred which makes the fewest number of assumptions.
Albert EinsteinThe scientific theorist is not to be envied. For Nature, or more precisely experiment, is an exorable and not very friendly judge of his work. It never says "yes" to a theory. In the most favorable cases it says "Maybe," and in the great majority of cases simply "No." If an experiment agrees with a theory it means for the latter "Maybe," and if it does not agree it means "No." Probably every theory will some day experience its "No" - most theories, soon after conception.
Albert EinsteinA successful man is he who receives a great deal from his fellow men, usually incomparably more than corresponds to his service to them. The value of a man, however, should be seen in what he gives and not in what he is able to receive.
Albert EinsteinWell, I have considered myself to be very fortunate in that I have been able to do mostly only that which my inner self told me to do... I am also aware that I do receive much criticism from the outside world for what I do and some people actually get angry at me. But this does not really touch me because I feel that these people do not live in he same world as do I.
Albert Einstein