Contradictory explanations for Iberian history can both be true.

Evidence

It is obvious … that the militant impetus and support for … Peninsular vivisection could not arise spontaneously… . The initial motivation of that rebellion does not lie in the proto-Portuguese character of that country… . That is why two apparently contradictory ways of understanding the origin of Portugal—my own and that of Portuguese historians who opposed it—can both be true. — Cedric J. Robinson, Black Marxism_ The Making of the Black…, 1778