“…The thesis was argued in Sidoli's important paper (Sidoli 2018b, 422-23), which also offers in footnote 45 a subtle argument on how to transform the proof of Elements I, 46 in order to make P4 unnecessary in it, even though the procedure cannot be generalized (the footnote also claims, I think wrongly, that Elements I, 14 and 15 do not need P4). For a fuller treatment of the notion of givenness, see also Sidoli 2018a. conclude that two triangles having equal sides are equal. When Euclid further applies this theorem (for instance in Elements I, 9), the triangles under consideration are given in position in a certain configuration, and nonetheless Euclid does not hesitate to make use of Elements I, 8 to conclude the demonstration-and similarly in all other cases.…”