Thus, by science I mean, first of all, a worldview giving primacy to reason and observation and a methodology aimed at acquiring accurate knowledge of the natural and social world. This methodology is characterized, above all else, by the critical spirit: namely, the commitment to the incessant testing of assertions through observations and/or experiments — the more stringent the tests, the better — and to revising or discarding those theories that fail the test. One corollary of the critical spirit is fallibilism: namely, the understanding that all our empirical knowledge is tentative, incomplete and open to revision in the light of new evidence or cogent new arguments (though, of course, the most well-established aspects of scientific knowledge are unlikely to be discarded entirely).. . . I stress that my use of the term 'science' is not limited to the natural sciences, but includes investigations aimed at acquiring accurate knowledge of factual matters relating to any aspect of the world by using rational empirical methods analogous to those employed in the natural sciences. (Please note the limitation to questions of fact. I intentionally exclude from my purview questions of ethics, aesthetics, ultimate purpose, and so forth.) Thus, 'science' (as I use the term) is routinely practiced not only by physicists, chemists and biologists, but also by historians, detectives, plumbers and indeed all human beings in (some aspects of) our daily lives. (Of course, the fact that we all practice science from time to time does not mean that we all practice it equally well, or that we practice it equally well in all areas of our lives.)
In AP Bio, I learned that the cells in our body are replaced every seven years, which means that one day, I'll have a body full of cells that were never sick. But it also means that parts of me that knew and loved Sadie will disappear. I'll still remember loving her, but it'll be a different me who loved her. And maybe this is how we move on. We grow new cells to replace the grieving ones, diluting our pain until it loses potency.The percentage of my skin that touched hers will lessen until one day my lips won't be the same lips that kissed hers, and all I'll have are the memories. Memories of cottages in the woods, arranged in a half-moon. Of the tall metal tray return in the dining hall. Of the study tables in the library. The rock where we kissed. The sunken boat in Latham's lake, Sadie, snapping a photograph, laughing the lunch line, lying next to me at the movie night in her green dress, her voice on the phone, her apple-flavored lips on mine. And it's so unfair. All of it.