Since reality is registered primarily through the registering of the size, the magnitude, or quantty of thing, does it follow that the reality of a thing is exhausted by its quantitative parameters?
In order to consider whether the reality of a thing is limited to registering its magnitude, we must first discuss the act of registering and then the category of quantities.
The act of registering requires use of the senses, and for Jaki this serves as the principal reminder about the reality of objects. However, Jaki highlights the fallacy of expecting too much from empiricism:
But trust in sensory perception, or commitment to empiricism, does not by itself lead one to the objectively real. Sensory perceptions as such are in the senses, in the subject. To recognise in sensory data the externally real is one of the main philosophical acts of true realism. Another of its main acts provides coherence to momentary sensory perceptions as so many indices of a reality existing even when the senses are dormant and counsciousness is not active.
Sensory perceptions are so many events. As such they can at most assure the occasional existence of things. Their togetherness can, in terms of a strictly sensationist philosophy of knowledge, hardly amount to more than a momentary kaleidoscope. True realism is about the continued existence of things, and, above all the continued consistent existence of the totality of things which is the universe." [The Only Chaos (p. 13-14)]
The tie of the mind with reality rests forever on the mind's trust in the word is or the verb that states that this or that thing does exist. In investigating any bit of matter, say a stone, the scientist must first assume that it exists. Only then can he logically investigate the quantitative properties of that things, although he as a scientist does not have to speculate any further about existence. But he cannot take lightly this foundation of his work. Then the danger arises that he would seek a false reason for foundation and turn reality into the function of some operation, preferably quantitative, of the mind. [Questions on Science and Religion p. 16]
However, Jaki notes "Is is simply ourside the grasp of exact science. Only a wild intellect would imagine that existence can be measured in grams, inches, or nanoseconds." (Science and Religion: A Primer p. 6)