What is a reality? We commonly believe that the things we see or perceive through our senses (or with the help of scientific instruments) are realities. All such things are forms of matter which are in fact modes of one reality called pudgala in Jain Philosophy. All physical things we know, from an atom or its sub particles to a planet or a star, are modes of the same reality pudgala. There are five other realities which exist in the universe. We feel the existence of some of them but all five are confirmed by omniscient who 'sees' the substances in their absolute and pure state. Our perception is limited and relative due to the frame of reference provided by our physical mind, and our beliefs. An omniscient sees the realities, physical and non physical, by his inner self without the help of senses and mind and therefore is able to perceive the realities in their absolute form. Although we cannot directly conceive all the realities, their existence is logically proved. The term reality or a substance is used in specific sense in Jain philosophy. This refers to the fundamental substances that constitute the Loka. Loka is also a technical term of Jain philosophy meaning the entire space in which all the six realities exist. The Loka is much bigger than the universe known to science as we shall see later. A substance (dravya) is capable of eternal continuous existence through infinite succession of origination and cessation. A substance is also the assortment of qualities / attributes. It experiences transformation or modification of its state. During this process of transformation the precedent mode ceases to exist and the succeeding mode originates but the basic nature of the substances is preserved in this change. This trinity of origination cessation permanence (OCP) is the basic characteristic of a substance. This rule applies to all substances and objects in nature. The attribute of permanence implies that a substance can neither be created nor destroyed; it can only change its form. Thus a substance is a reality or truth having permanent existence through change. Anything that does not confirms to the OCP rule is not a reality or a substance. All objects are, in fact, transitory permanent i.e. they are transient in respect of modes and attributes and permanent in respect of their basic substance hood. No object can be purely transitory or purely permanent. This is true of all objects whether living or non-living, physical or non physical, subtle or gross.