Empty space in Jainism is referred to as Alokasha. Jain religion sets out five non-conscious substances, namely, matter, time, space, motion and rest. Space, termed akasha, is considered as one of the astikaya substances, as it possesses the quality of extension. All substances except time have extension and extension is afforded only by space. Space itself is not extension; it is the locus of extension. Two kinds of space are distinguished. The first is alokakasha, which is empty space, the other is lokakasha. The division into lokakasha and alokakasha is not in akasha itself, which is a single substance. The division arises due to its relation with other substances. Space is self-supported, while other substances, with the exclusion of time, are not so but are accommodated within it.
Alokakasha is imperceptible and eternal in nature. It is pure space which extends infinitely beyond the universe. In this space, no substance of the universe exists. Akasha is an all-comprehensive container enclosing the universe and non-universe. The distinction of lokakasha and alokakasha is based on the presence of the media of motion and rest. If the medium of motion does not exist in lokakasha, there can be no condition for movement and there can be no distinction of universe and non-universe. Similarly, if the medium of rest does not exist, there can be no condition assisting rest. Things will not be stationary. There can, then, be no distinction of universe and non-universe. Therefore, owing to the existence of both the media of motion and rest, termed dharma and adharma respectively, the distinction of lokakasha and alokaksha is established.