The five out of six substances are classified as ”astikaya”. These are ”jîva”, matter, space, ”dharma” (medium of motion) and adharma. “Astikaya” consists of two words, “Asti’ and “Kaya”. ‘Asti’ literally means exists.
Now, the five kinds of substance , viz. Jiva, Pudgala , Dharma, Adharma and Akasa always exists, hence, while mentioning any of these , one might says, “it exists”. Again each of these substances has many Pradesas, like bodies. Hence each of these might also be said to be “Kaya” (literally, body).
These two characteristics being combined, each of the aforesaid five substances are named “Astikaya” or ‘that which exists and has different Pradesas like a body’. It should be remembered that to be an Astikaya, a substance must have both these characteristics.
The substance Kala (Time), though having the first characteristic (viz. existence), is not called Astikaya, because it does not have many Pradesas.
To be more clear, first let us understand what is meant by a Pradesa. Pradesa has been defined in Verse 27 to be that part of space which is obstructed by one individual atom of matter. A Pradesa can contain not only atoms of matter, but the particles of other substances also.
Thus each of the substances have Pradesas. Now, Jiva, Pudgala, Dharma, Adharma and Akasa have many Pradesas, as these consist of many indivisible and inseparable parts, or, in other words, the particles of these are not separate, but are mixed up or capable of being mixed up.
Hence, as we are unable to locate these particles indefinite Pradesas, these substances can be said to occupy many Pradesas. But Kala consists of particles which never mix up, and consequently each of these particles occupies a particular Pradesas.
Hence Kala is said to have one Pradesas only. But the other substances Jiva, Pudgala, Dharma, Adharma and Akasa having no separable and distinct particles occupying distinct Pradesas, are said to be of many Pradesas.
Kaya is that which has many Pradesas . The five substances, Jiva, Pudgala, Dharma, Aharma and Akasa have many Pradesas, and hence these are called Kayas; but Kala having but a single pradesa, is not called so. This is the reason why Kala is not called an ‘Astikaya’.