That's the nub of the thing, you see seriousness of spirit. It doesn't mean heaviness of heart, or a lack of fantasy, but it does mean an awareness of influences that touch our lives, sometimes in ways that seem cruel and unfeeling, and sometimes in ways that open up a glory which can never be forgotten.
What means this heaviness that hangs upon me? This lethargy that creeps through all my senses? Nature, oppress'd and harrass'd out with care, Sinks down to rest.joseph addison
Weep bitterly over the dead, for he is worthy, and then comfort thyself; drive heaviness away: thou shall not do him good, but hurt thyself.Matthew Arnold
Give unto them beauty for ashes, the oil of joy for mourning, the garment of praise for the spirit of heaviness.
They say there is a difference between actual temperature and perceived temperature, but in the “bearable heaviness of being” the actual measure is no doubt the weight we perceive.
I mentally conceive of some moveable [sphere] projected on a horizontal plane, all impediments being put aside. Now it is evident... that equable motion on this plane would be perpetual if the plane were of infinite extent, but if we assume it to be ended, and [situated] on high, the movable, driven to the end of this plane and going on further, adds on to its previous equable and indelible motion, that downward tendency which it has from its heaviness. Thus, there emerges a certain motion, compounded...