At what point does an inside become an outside? The house I grew up in has a large, purple wooden door with a simple brass knob and I have passed through its threshold an uncountable number of times. I have done this effortlessly and yet if one considers this act, of transitioning between two sides of a “boundary”, one may find it in need of some explanation. At what point, in my journey “through” the door, did I suddenly become inside or outside of the house? The answer that seems the most simple is indeed the correct one: In between the two. However true this response, it does not lay to rest the question that lurked beneath the first. What does it mean to be “in between” two things?
As I walked through my front door it seems certain that, in some moment, my body was perfectly situated in some plane that subdivided the doorway into exactly equal portions. And yet, one may wonder what does it mean to be on the surface of that plane. Is there a distinct surface of atmospheric molecules that are “inside” air molecules and another that consists of “outside” air molecules? Is there a distance between the two, or do they abut and interact? A doorway is a silly example, of course, but these questions are not exactly trivial ones. As one attempts to hone in on the boundary between two entities, it is no easy task to say where one thing begins and the other ends. For example, in many ways the debate over when a fetus become a living being (and thus is entitled to the protection of its right to life) is a debate over this very issue. When does a collection of tissues and cells begin to possess the organizational structure that we would call “living”? Biofilms provides a similar challenge. Biofilms are aggregates of otherwise single-celled organisms that seem to be conducive to a form of organization that results in the coordination of gene expression among single cells depending on the density of cells in that region of the biofilm (this type of “communication” is referred to as quorum sensing). Should we refer to the biofilm as an organism if it “coordinates” multiple individual cells, as is the hallmark of complex multicellular organisms like ourselves? If not, then might we then have to refer to our individual cells as organisms?
My point here is that the interface between two things is messy; boundaries are often blurry and indistinct, and yet we behave as if it is a certainty that there are truly boundaries, that two entities are quite distinct from one another and indeed that there are any such things as entities at all! Now, I certainly do not wish to argue that boundaries are a hopeless notion, quite the contrary. Rather, with this blog I hope to investigate these “in between places”, the threshold between one thing and another, and to determine how a characterization of these boundaries reflects upon and informs our understanding of the entities which comprise the two halves of the boundary in question. My predominant education has been in Biology, but I aim not to limit my discussions in this blog to biological boundaries. I aim instead to investigate any and all boundaries as best I can, with the utmost rigor and journalistic flair that I can muster. I hope that this blog becomes a place for both me and anyone who reads it to learn and to grow in our understanding of the world. Your comments and questions will always be welcomed and appreciated. If you are reading this, please stay tuned for the first step in my journey into the space between things.