Shirkers each struggling to place upon his god the burden whose carrying and whose carrying alone can give him strength to walk free and unafraid, himself godlike among the stars." And now distinctly, unfalteringly, the voice went on: "Dominion over all the earth?
Yes--as long as man is fit to rule; no longer.

Science has warned us.

Where was the mammal when the giant reptiles reigned?
Slinking hidden and afraid in the dark and secret places.

Yet man sprang from these skulking beasts.
"For how long a time in the history of earth has man been master of it?
For a breath--for a cloud's passing.

And will remain master only until something grown stronger wrests mastery from him--even as he wrested it from his ravening kind--as they took it from the reptiles--as did the reptiles from the giant saurians--which snatched it from the nightmare rulers of the Triassic--and so down to whatever held sway in the murk of earth dawn.
"Life! Life! Life! Life everywhere struggling for completion! "Life crowding other life aside, battling for its moment of supremacy, gaining it, holding it for one rise and fall of the wings of time beating through eternity--and then--hurled down, trampled under the feet of another straining life whose hour has struck.
"Life crowding outside every barred threshold in a million circling worlds, yes, in a million rushing universes; pressing against the doors, bursting them down, overwhelming, forcing out those dwellers who had thought themselves so secure.
"And these--these--" the voice suddenly dropped, became thickly, vibrantly resonant, "over the Threshold, within the House of Man--nor does he even dream that his doors are down.