But the certainty of astronomy arises from the fact that it has for its basis the intuition or perception of space, which is given a priori, and is therefore infallible. All space-relations, however, follow from each other with a necessity (ground of being) which affords a priori certainty, and they can therefore be safely deduced from each other.
Azken horren ziurtasuna a priori emandako, beraz hutsezina den espazioaren begiespen bat oinarrian izatetik dator, harreman espazial guztiak bata bestetik beharrezkotasun batekin (izatearen arrazoia), zeinak a priori ziurtasuna ematen baitu, jarraitu eta horregatik ziurtasunez bata bestetik deduzitzen baitira.