Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.

Though wise men at their end know dark is right,
Because their words had forked no lightning they
Do not go gentle into that good night.

Good men, the last wave by, crying how bright
Their frail deeds might have danced in a green bay,
Rage, rage against the dying of the light.

Wild men who caught and sang the sun in flight,
And learn, too late, they grieved it on its way,
Do not go gentle into that good night.

Grave men, near death, who see with blinding sight
Blind eyes could blaze like meteors and be gay,
Rage, rage against the dying of the light.

And you, my father, there on the sad height,
Curse, bless, me now with your fierce tears, I pray.
Do not go gentle into that good night.
Rage, rage against the dying of the light.

Dylan Thomas, 1914 - 1953
The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must in some shape or other visit the human race. The vices of mankind are active and able ministers of depopulation. They are the precursors in the great army of destruction, and often finish the dreadful work themselves. But should they fail in this war of extermination, sickly seasons, epidemics, pestilence, and plague advance in terrific array, and sweep off their thousands and tens of thousands. Should success be still incomplete, gigantic inevitable famine stalks in the rear, and with one mighty blow levels the population with the food of the world.
Malthus T.R. 1798. An essay on the principle of population. Chapter VII, p61

At some time in the relatively near future, we will have both the computing power and the brain knowledge to be able to create artificial realities that we will be able to plug our brains into that will give no indication that they are anything but real. We will be able to create any kind of reality, any kind of experience you can imagine.

Once a civilization is able to do that, it may very well be that they will have no other desires beyond increasing their computing power, extending their life spans, and protecting themselves from planetary disasters. This might be the key to the fact that we have not detected any advanced civilizations.

Damien Valdes (Commenting on io9’s “Some of the most plausible scenarios for alien civilizations.”)