"Proust viewed involuntary memory as containing the "essence of the past", claiming that it was lacking from voluntary memory. In his novel, he describes an incident where he was eating tea soaked cake, and a childhood memory of eating tea soaked cake with his aunt was "revealed" to him.[1] From this memory, he then proceeded to be reminded of the childhood home he was in, and even the town itself. This becomes a theme throughout In Search of Lost Time, with sensations remind Proust of previous experiences. He dubbed these Involuntary memories."

[joseph berg]

- Proust viewed involuntary memory as containing the "essence of the past",
claiming that it was lacking from voluntary memory. In his novel, he
describes an incident where he was eating tea soaked cake, and a childhood
memory of eating tea soaked cake with his aunt was "revealed" to
him.[1]<http://en.wikipedia.org/wiki/Involuntary_memory#cite_note-Mace2007-0>
From
this memory, he then proceeded to be reminded of the childhood home he was
in, and even the town itself. This becomes a theme throughout *In Search of
Lost Time*, with sensations remind Proust of previous experiences. He
dubbed these Involuntary memories.

http://en.wikipedia.org/wiki/Involuntary_memory