If a physicist were to successfully reconcile general relativity and quantum mechanics, it would undoubtedly be a monumental achievement and a major breakthrough in our understanding of the fundamental laws of nature. It would be a significant milestone in the history of physics and could potentially revolutionize our understanding of the universe.
However, the title of the "greatest physicist of all time" is a subjective designation and is typically influenced by various factors, including the overall contributions of the physicist to the field, the impact of their work on scientific knowledge, and the influence of their ideas on subsequent generations of scientists.
Many physicists have made profound contributions throughout history, including Albert Einstein for his theory of relativity, Isaac Newton for his laws of motion and universal gravitation, and Niels Bohr for his work on atomic structure and quantum theory, to name just a few. Each of these physicists has left an indelible mark on the field of physics and has significantly advanced our understanding of the natural world.
If a physicist were to successfully reconcile general relativity and quantum mechanics, their achievement would undoubtedly place them among the most influential and celebrated physicists in history. However, whether they would be considered the "greatest physicist of all time" would ultimately depend on the overall impact and significance of their work in the broader context of physics and the judgments of the scientific community and future generations.