William Blake, John Keats and William Wordsworth all believe in the "depth" of the world and the possibilities of the human heart. However, each poet looks towards different periods in time to capture meaning in life. Blake looks towards the future for his inspiration, Keats towards the present and Wordsworth towards the past. Regardless of where each poet looks for their inspiration they are all looking for the same thing; timeless innocence. Each poet sought to transcend time by creating works that dealt with life, death, hope and imagination and to discover some kind of deep truth or meaning in existence. Life and death is an issue that we will all have to deal with at some point in our life and like all Romantics they sought to give it meaning.
To say that Blake looked towards the future in his poetry would be correct but would not be entirely accurate. Yes, Blake did look towards the future but more specifically he looked at the change of a person's soul from innocence to experience. Blake was most interested in the maturing process that one's goes through in life as they grow older. The growth from the naïve and innocent lamb to the sophisticated and experienced tiger is what we will eventually have to happen if we hope to survive in the world of experience.
Blake sees the move from innocence to experience similarly to the encroachment of the city into nature. Whereas nature would seem to be its own all encompassing world he understands that the city is not and eventually it will intrude on the country life regardless of whether it is ready for it or not. Blake uses this encroachment as metaphor for how the world of experience moves in on the child during adolescents. Though experience is often harsh, cold and violent it is a nessesary evil and it is a necessary balance to innocence.
Blake was not born wealthy and thus has a very realist outlook on life and understands that it is a sink or swim kind of world.