Without remembrance one may as well be dead because during times of neglect, one is not remembering his purpose and therefore h e is not doing a useful act. Hence, the hadith of the Prophet (peace and blessings of Allah be upon him), "The similitude of the one who remembers his Lord and the one who does not remember his Lord is like the similitude of death and life." (Bukhari, Muslim)
This real life that the Prophet is referring to is the life of the purified person who remembers Allah and recognizes his purpose in life. He does not wander about aimlessly not recalling why he is even existing.
There are two distinct modes of dhikr or remembrance of Allah. One is a constant and continuous form of dhikr wherein the person is always mindful of Allah as he goes about his daily routine and affairs. This form of dhikr, though, is developed and assisted by the more formal form of dhikr wherein a person remembers Allah at specific times via the means of specific words that have come from the Prophet. In fact, the most important of these formal means is the prayer itself.
"Purification of the Soul" - Jamaal al-Din M. Zarabozo, pp. 318, 319