Report by Alfred North Whitehead, on his paper by 'Mathematical concepts of the material world' Comments from the author, on the referee's comments. He cannot undertake the change that the referee recommends, as the paper is already presented in a 'convenient' manner for a careful student. He has added references to the paper. One referee suggested that the theoretical symbols should be collected on one page for early reference. He has not been able to do this, as he has already compressed the symbols as much as possible. [Published in Philosophical Transactions A, 1906]. December 1905