We try to segregate ourselves from the external, and this creates a kind of gigantic bubble in us which consists of nothing but air and water, or in this case, fear and the reflection of the external thing. So this huge bubble prevents any fresh air from coming in, and that is "I" –– the ego. So in that sense there is the existence of ego, but it is in fact illusory. Having established that, one generally wants to create some external idol or refuge. Subconsciously one knows that this "I" is only a bubble and it could burst at any moment, so one tries to protect is as much as one can –– either consciously or subconsciously. In fact we have achieved such skill at protecting this ego that we have managed to preserve it for hundreds of years. It is as though a person has a very precious pair of spectacles which he puts in a box or various containers in order to keep it safe, so that even if other things are broken this would be preserved. He may feel that other things could bear hardship, but he knows this could not, so this would last longer. In the same way, ego lasts longer just because one feels it could burst at any time