it is a metaphysical truth, and as such, just as certain as the principle of contradiction itself, which is a metalogical truth, and the common foundation of all logical demonstration.
egia metafisiko bat da eta horrelakoa den heinean kontraesanaren printzipioa bera bezain bitartegabeki ziurra da, zeina egia metalogiko bat eta frogapen logiko ororen oinarri orokorra baita.