(Please don’t copy and paste from g00gle) Read the following excerpt from Ted Chiang's "Exhalation":

I was a proponent of the competing school of thought, which
held that our memories were stored in some medium in which
the process of erasure was no more difficult than recording:
perhaps in the rotation of gears, or the positions of a series of
switches. This theory implied that everything we had forgotten
was indeed lost, and our brains contained no histories older than
those found in our libraries. One advantage of this theory was
that it better explained why, when lungs are installed in those
who have died from lack of air, the revived have no memories and
are all but mindless: somehow the shock of death had reset all
the gears or switches. The inscriptionists claimed the shock had
merely misaligned the foil sheets, but no one was willing to kill a
living person, even an imbecile, in order to resolve the debate. I
had envisioned an experiment which might allow me to
determine the truth conclusively, but it was a risky one, and
deserved careful consideration before it was undertaken. I
remained undecided for the longest time, until I heard more news
about the clock anomaly
We are not really consuming air at all. The amount of air that!
draw from each day's new pair of lungs is exactly as much as
seeps out through the joints of my limbs and the seams of my
casing, exactly as much as I am adding to the atmosphere
around me; all I am doing is converting air at high pressure to air
at low. With every movement of my body, I contribute to the
equalization of pressure in our universe. With every thought that!
have, I hasten the arrival of that fatal equilibrium

Identify two themes conveyed in this excerpt. How do these themes develop over the course of the story? Be sure to refer to examples from the excerpt or story to support your analysis.