Abstract: The "scientific metaphysics" envisaged by Immanuel Kant and Edmund Husserl is of course impossible, but a quantitative metaphysics based on apperception in a certain sense can make comparative judgments on the mental quantity and mental density of all beings. Metaphysical existence is spiritual existence. The universe is a higher spiritual existence than human beings. The universe of absolute disorder and the universe of absolute order cannot occur because of their constant and unchanging, so they belong to the impossible universe; all possible universes are hypercycles. The moving universe is the spiritual universe. The essence of material movement is spiritual movement. Since spirit is not the existence of space and time, we cannot measure the value of the spiritual quantity of a certain existence in the same way as measuring the volume, mass and movement speed of the existence in space and time. However, people and I always recognize and comprehend the representations in the world received by their own senses with their perceptual-intellectual-rational (as a whole of thinking) simultaneously, which is apperception. Based on apperception, it is possible to judge the magnitude of metaphysical existence (spirit). For example, judging that the spiritual quantity of human beings is greater than that of any animal or plant on the earth, and the spiritual quantity of the universe must be greater than that of human beings. Based on this, it can be further deduced that the spiritual density of the material world is less than the spiritual density of the biological world, and the spiritual density of the biological world is less than the spiritual density of the human world. It is further deduced that as the spirit (God) corresponding to the "collection of the whole universe", its quantity is greater than the spiritual quantity of any specific universe, and the spiritual quantity of any one universe is greater than the spiritual quantity of the part that constitutes the universe, which is because the whole as a total of part is greater than part.