I saw this the other day, quoted on Diane Duane’s tumblr:
You want a physicist to speak at your funeral. You want the physicist to talk to your grieving family about the conservation of energy, so they will understand that your energy has not died. You want the physicist to remind your sobbing mother about the first law of thermodynamics; that no energy gets created in the universe, and none is destroyed. You want your mother to know that all your energy, every vibration, every Btu of heat, every wave of every particle that was her beloved child remains with her in this world. You want the physicist to tell your weeping father that amid energies of the cosmos, you gave as good as you got.
And at one point you’d hope that the physicist would step down from the pulpit and walk to your brokenhearted spouse there in the pew and tell him that all the photons that ever bounced off your face, all the particles whose paths were interrupted by your smile, by the touch of your hair, hundreds of trillions of particles, have raced off like children, their ways forever changed by you. And as your widow rocks in the arms of a loving family, may the physicist let her know that all the photons that bounced from you were gathered in the particle detectors that are her eyes, that those photons created within her constellations of electromagnetically charged neurons whose energy will go on forever.
And the physicist will remind the congregation of how much of all our energy is given off as heat. There may be a few fanning themselves with their programs as he says it. And he will tell them that the warmth that flowed through you in life is still here, still part of all that we are, even as we who mourn continue the heat of our own lives.
And you’ll want the physicist to explain to those who loved you that they need not have faith; indeed, they should not have faith. Let them know that they can measure, that scientists have measured precisely the conservation of energy and found it accurate, verifiable and consistent across space and time. You can hope your family will examine the evidence and satisfy themselves that the science is sound and that they’ll be comforted to know your energy’s still around. According to the law of the conservation of energy, not a bit of you is gone; you’re just less orderly. Amen.
– Aaron Freeman, “You Want A Physicist To Speak At Your Funeral”
Unfortunately (and admitting that from certain nonphysically spiritual points of view, it is a lovely sentiment) you do rather have to hope that there’s not a physicist listening at your funeral, who knows full well that it’s the orderliness that’s the point, belike, inasmuch as while yes, all energy is conserved, all meaning and purpose and love and warmth and memory and other patterns in the energy will have vanished even before the time when the universe is reduced to a flat, cold, soup of unbonded particles in the inexorable grip of energy-conserved heat death.
And more to the personal point, physics – with a little help from information theory – is quite able (in theory; the practical side isn’t quite there yet) to compute the point in the hours after – or even potentially before, with some medical conditions – your corporal death at which all of the youness of you has been lost from the cooling meat that used to be your brain.
Anyway, to bring this back to in-universe relevance, not only did this realization synergize well with existing eldraeic spiritual beliefs (which had long held that the soul stayed attached to the body until it was destroyed; which is why they were cremators, it being impolite to keep your deceased family and friends glued into a decaying corpse, belike), but also provided the catalyst for that Middle Information Age pre-funerary custom of whacking the heads off the deceased without delay and immuring them in colossal underground shrine-vaults filled with Dewar flasks of liquid nitrogen…
(It had some interesting effects when they were finally able to recover all of that mind-state data, too, but that’s another tale…)