Albert Einstein I don't know if it could be out of fear, or the reason was a contrary, earth-shaking implication that embarrassed him because it did not line up with his worldview. However, the Theory of Special Relativity---and General Relativity---implied the beginning of the universe and that did not set well with him or his colleagues who advocated a Steady State Universe with no beginning.
So fearful he was of upsetting the apple cart (and fearful of its philosophical implications) that he invented the infamous fudge factor (universal constant). Which he later admitted was the worst mistake of his mathematical career!
Fortunately, Einstein overcame his fear, and admitted that the beginning of the Universe was a definite possibility.