So much has happened in the past month. Events that have had profound impacts on myself and those around me. And yet, I find myself wanting to simply return to the topic I ended on from my last post. So today I am going to continue trying to answer the question from my last post: Do I have a relatively fixed time?
To attempt to answer this question, I feel I need to make clear what I am in the previous dimensions first. To try and elucidate precisely what it means to have a length or a width or a depth. And perhaps even more than that, to try and imagine what would happen if I were to somehow remove one of these dimensions; how might the others react in such a situation?
Recently, in a class I have been taking in physics, we have been discussing what precisely “mass” is. This first needs to be separated from the distinct idea of what “weight” is. My weight is a measure of how much the Earth’s gravity is pulling upon my body. The equation to describe weight is w = mg, where w represents weight, m represents mass, and g represents the acceleration due to gravity. That is to say, mass has a relationship to weight, but mass is not the same as weight. I feel my weight, as I am constantly being pulled toward the ground below me. In fact, the very idea of “below me” is in large part because I have weight; that weight exists in the direction I feel pulled is what I refer to as “below me.”
What was made clear in my class about mass is that mass is the idea of resisting change. To be more specific, the idea of “inertia” was brought up in order to explain mass. So what is “inertia” exactly?
The word “inertia” starts with the word “inert.” The idea is that objects have a sort of preference to remain as they are, to remain inert. This is in fact Newton’s First Law (translated): “Every object perseveres in its state of rest, or of uniform motion in a right line, except insofar as it is compelled to change that state by forces impressed thereon.” Stated simpler, Newton is suggesting that objects will remain at a constant speed at all times, unless something causes them to change their speed. An object could be at rest (not moving at all), or it could be moving at a constant speed in some direction, but unless a force acts upon it, it will continue to do so indefinitely.
This is where the idea of acceleration and impulse becomes important. To change an object, one accelerates the object using a force. Applying a force to an object changes its speed. An impulse is simply applying a force over a (usually) brief period of time. With this concept in our minds, inertia is how the object resists the change to its speed. This is why it is harder to change the motion of certain objects than others. Those objects that require more force to change their speed we refer to them as having greater mass.
To sum up, mass is a measure of how much force it takes to change an objects speed. Mass is a measure of the inertia of the object. In simplified terms, mass is the objects resistance to change. And following from this, weight is a measure of this resistance multiplied by the acceleration due to gravity. In other words, weight is the force applied by the Earth to change the object’s speed and propel it toward the Earth.
Another feature that tends to be thought about with mass is that it must occupy some space. Meaning an object of some mass will have some length, width, and depth. These dimensions help me describe how the object is occupying the space, and suggest to me that there is some relationship between mass and the space it occupies. As reluctant as I was in my previous post, it seems I am compelled to start discussing identity now.
What makes me me is what I would refer to as my identity. More generally, the identity of any object is the thing that makes that object that object and not some other object. Or, similarly, what makes an object that object and not the environment that surrounds that object. I am me, but I am somehow separate from the world around me. But at the same time I am clearly also a part of the world around me. But I do not consider myself to be the world around me. Usually, I separate what is me from the world around me. So there seems to be some sort of barrier that separates what is me and what is the world around me.
The dimensions of length, width, and depth are in some way delineating that barrier that separates me from the world around me. So, as it turns out, my identity is bound up significantly in what space I occupy. Thus, if these three dimensions are helping delineate what makes me me, then if I want to talk about a fourth dimension, time, then I should be talking about how time helps delineate what is me from what is the world around me.
When I walk down the street, I notice how there is a small amount of atmosphere that travels with me. Within a few centimeters of my skin, small insects will sometimes get caught up in that small amount of atmosphere around my body. I walk, and those insects are unable to escape and fly away, trapped in that pocket of air. It is annoying having those insects buzzing around my head as I walk. Do I consider that pocket of air me? Do I consider those insects trapped in the pocket of air me? Obviously not. They are outside what I consider me. For me, I clearly want to suggest that the boundary of my skin is the boundary of what is me. The boundary of my skin can easily be measured using length, width, and depth. But what about time?
I keep orbiting the question, trying to imagine in what possible way I am bounded by time. The answer I often come to is that my birth and my death are the bounds of my identity, but that just doesn’t feel correct. Especially when thinking about things like time travel and how it might operate. It seems like the coming into existence and the leaving existence are too far removed from the bounds I want to talk about.
An alternative is to consider this moment in time. The “now” that I have talked about before. I exist here and now, in this moment. My identity could be bound by “now” in a very literal sense. That which exists in the past is no longer bound to my identity and the future that has not yet come to pass is not bound to my identity either. If I use this model to describe my identity, then perhaps I am simply razor thin, spanning a mere moment in history. This sort of interpretation seems consistent with what most people think about when considering time travel, as my perceptual reference of now is all that seems to matter when moving about a timeline.
Thinking back to the film Slaughterhouse-Five, it seems like that is what people have in mind when suggesting it is a film about time travel. The protagonist’s “now” is literally jumping from moment to moment along his personal history. But then it is only his non-material identity that is jumping around, as his body does not travel with him from moment to moment. It seems like a partial or incomplete time travel if this is the case. Hence why my interpretation in my previous post seems the better interpretation. I think I want to say that for time travel, my entire identity needs to travel from one time to another, meaning both my mind and my literal body as well.
Does this all make sense? I am not entirely sold on this theory myself. But it is a start. To suggest my identity is bound up in these four dimensions, length, width, depth, and time, I have to look at myself in a certain way. And, as with the idea of a mass being a resistance to change, whatever is taken to be me is similarly resistant to change without a significant outside force.