Who came up with the concept that geologic processes operating at present are the same processes that operated in the past?

James Hutton

Explanation:

James Hutton was the geologist who brought this concept of 'Uniformitarianism'. This law describes that all the geological processes that occur now must have taken place in the geological past, with varying intensities, and these processes are responsible for the configuration of the landscape and formation of various surface features on earth.

This was an important discovery that led to a better understanding of the geological processes and how they act on the earth's surface and in its interior.