The Buddha explains how if shapes, sense-experiences, perceptions, own-making and consciousness were not identified with now, there would be no future existence of identified-with shapes, sense-experiences, perceptions, own-making and consciousness and the pain they bring with them.
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Note here the translation of 'sankhata' (a synonym for sa'nkhaaraa) is translated by Woodward and Bhk. Bodhi (and as one possibility in the PED) as 'conditioned.' This carries with it the same problems that translating sa'nkhaaraa as 'conditioned' creates. One is supposed to see that 'sankhata-ed' consciousness is a problem (because it has been sankhta-ed it has come into existence and will pass out of existence), but translating it this way we must also accept the idea that the consciousness that is equivalant to Nibbana cannot be 'conditioned'. But it is conditioned. It is just not sankhata-ed: own-made. It has come about as a result of not-doing - the not-doing of those things described in the Magga. It has not been made as a result of the identification by an individual with the intent to create experience which is sankhata-ing. If you don't have this distinction you cannot find Nibbana. You will find yourself in an endless battle with the idea of the obliteration of consciousness and the idea that Nibbana is not annihilation. Consciousness arises based on conditions. Some conditions cause consciousness to arise as to a self: those forms of consciousnes which have been own-made. The forms of consciousness which have been own-made are unstable. That form of consciousness which has been conditioned by not-doing has not been own-made. Not having been own-made it does not enter existence. Not having entered existence it does not pass out of existence. It has as it's object freedom from the own-made. With that as it's object, it is stable.