I'm surfing the giant life wave.--William Shatner
If you don't know about qualia, here's a thought experiment:
Mary the colour scientist knows all the physical facts about colour, including every physical fact about the experience of colour in other people, from the behavior a particular colour is likely to elicit to the specific sequence of neurological firings that register that a colour has been seen. However, she has been confined from birth to a room that is black and white, and is only allowed to observe the outside world through a black and white monitor. When she is allowed to leave the room, it must be admitted that she learns something about the colour red the first time she sees it — specifically, she learns what it is like to see that colour. (source: Frank Jackson)
This supposed thing Mary learns philosophers call qualia. It is the private experience of a thing, the sense of a pedal stroke, the wind in your face, the feeling you and I feel but cannot be sure we share.
It is hard to explain qualia if you only believe in physical things. Said Erwin Schrödinger:
The sensation of colour cannot be accounted for by the physicist's objective picture of light-waves. Could the physiologist account for it, if he had fuller knowledge than he has of the processes in the retina and the nervous processes set up by them in the optical nerve bundles and in the brain? I do not think so.
Another way of seeing this is that knowing that is not the same as knowing how.
I know that a wave is a disturbance or oscillation that travels through space and matter, accompanied by a transfer of energy.
But I also know how it feels for a wave to flow through ocean water.
I know that a peleton is a group of cyclists who ride close together to mitigate the effects of aerodynamic drag. But I also know how it feels to ride in a peleton.
You get the idea.
You know that Spring starts when we start removing arm warmers and start riding in the ever-later-setting sun. You know that it means the revival of nights at Hains and goon rides, the return of less devoted riders to the roads (i.e., freds). You know that it means the start of racing.
But I'm hoping you also share with me the knowing how of being a cyclists in Spring, of returning to feelings you have felt before and the long winter has blurred in forgetfulness. It's these qualia we miss most, isn't it, as we age? We may be annoyed by forgetting the telephone number, but we truly miss the sensation of loved ones. We may regret how we can no longer push out the watts, but we truly long for those glorious rides where the sun warms the arms and we are wrapped in the embrace of a lazily chatting peleton too content to contest the sprint points.
Isn't it crazy that our brightest memories are the most ephemeral--the very things beyond the realm of physics to explain, record, or capture?