What is Time?
Despite being something which nearly everyone appeals to throughout the entirety of his thinking life, the idea of Time is not very easily understood. Most people have never even thought to ask the question, "What is time?" let alone put serious effort into seeking an answer. Those who have quickly realize that the topic is far more complex than they'd thought.
When the average person thinks about time, they have this sense of something flowing ever forward. The past is behind us and gone. The future is ahead of us and unwritten. The present is the only thing that is real and it constantly slinks away into the past.
This sort of description is the basis for Tensed theories of Time-- sometimes also referred to as "Temporal Becoming" or "A-Theory." While there are specific models within the overarching group of Tensed Theories which have slightly different implications, the main idea is this notion that the future is not a thing which really exists. We can speculate about the possibility and potential of what may happen in the future; but those potentialities are not real, existing events until they are instantiated in the present.
In contrast, we can look at Tenseless theories of Time, sometimes called "Block Universe" or "B-Theory." Certainly far less intuitive, Tenseless models treat past, present, and future all as being equally real. The future is set in stone and though we seem to only experience it sequentially, one moment at a time, the things that will happen tomorrow are no less real than the things which are happening right now and the things which happened yesterday.
Given the fact that the A-Theory accords so well with our common experience, one might ask why anyone would ever ascribe to the B-Theory.
A Bit of Autobiography
My own journey in this regard may be somewhat unique. I was born into an Evangelical Christian home with devout parents, so I grew up with a very active religious education. One of the things which I had been taught, as is common within Christian theology, is that God is omniscient and all-knowing. God knows the entire story for everything, including all of the past, present, and future. In my mind, having been raised with this notion of omniscience since before I was even able to speak, it only made sense that if God knows the future then the future must be something real, something which exists and therefore can be known. While I certainly had the same experiential notion of time's flow that everyone has, it just seemed obvious to me that the future must already be fixed in some way. If God knows what I will do in the future, then it is logically impossible for me to do otherwise.
Whenever I talked to other people about these ideas, I found that they were really attached to the idea that the future is not set in stone and that the common-experience version of time must be true. However, I found my questions were very often hand-waived away with glib responses about "free-will" or "mystery" or other things which really didn't satisfy me. To be fair, I was just a little kid, so the only people I talked to about this were my parents, my friends, and my Sunday School teachers. It's hardly surprising that none of them were able to give me sophisticated answers to my questions.
As I got older, I started to have a boyish fascination with science. I loved my Math and Science classes in grade school and any time I could, when doing a History report, I chose to focus on a famous scientist. One of my particular heroes, at that time, was Einstein and I remember doing a massive report on him. We were supposed to come up with a 5-minute report to present in front of the whole class. After 15 minutes, the teacher cut me off and said we had to move on to other students. While I was still very young and didn't have the tools to completely understand what I was reading, I remember being absolutely ecstatic when discovering Relativity. It was the first time I had ever seen an explicitly tenseless idea of time laid out anywhere and it seemed like every weird thought I had conceived about how time works was suddenly being confirmed by science.
When I eventually started learning algebra, geometry, calculus, and physics, I began to realize that there were a lot of implications from Relativity on Time which I had not yet considered. Learning about these only bolstered my feeling that Time couldn't be as simple as the naive, common-experience approach to which my friends had all seemed so thoroughly attached.
Now that I am no longer a theist, obviously God's omniscience is no longer one of the reasons that I am convinced of the B-Theory. However, I find the evidence from philosophy, Special Relativity, General Relativity, and even more obscure areas of science to be so compelling that I remain a committed B-Theorist, to this day.
Relativity and Time
If you are unfamiliar with the science, you may now be wondering what Einstein's Relativity has to do with how we understand Time.
On the common-experience idea of time, we have this notion that the passage of time is the same for everyone and everything. If one second passes for me, then one second also passes for you and for a tree outside and for the Sun and for everything in the universe. Because of this, we have this notion that two different events can happen at exactly the same moment in time; that is to say, two different events can be simultaneous with one another.
In 1905, a young Albert Einstein published a paper describing what we now call "Special Relativity." I won't get into the specifics here, for the sake of brevity, but there are tons of amazing resources available on the Internet for anyone interested in learning precisely how Einstein came to his conclusions, and it is actually far easier to understand that reasoning than most people seem to believe. If you can handle some very basic, grade-school level algebra, you have all the math you need to understand the basics of Special Relativity. Long story short, Einstein's Special Relativity completely overturned these common-experience ideas about how time passes and whether two events happen simultaneously. The very strange truth of the matter is that time can pass differently for different observers depending upon how quickly they are in motion relative to one another. Because of this, two events which appear to be simultaneous for one observer might not be simultaneous to others seeing the same thing.
There was a significant catch, however. Einstein realized that his mathematical formulation of these phenomena only worked when discussing objects which are moving at constant velocities. The mathematics breaks down when we try to consider things which are accelerating or decelerating or not simply moving in straight lines. This is why we call it "Special Relativity," because the theory only applies to special cases.
Though it took Einstein more than a decade, lots of help from his friends, and much, much more complicated mathematics, in 1916 he managed to publish another paper which generalized his ideas about relativity so that they applied even in cases of acceleration, deceleration, and non-linear motion. The implications of this work on Time were even weirder than those of Special Relativity. On General Relativity, Time is a dimension of positional measure, very similarly to the way the three dimensions of space are. This alone implies the B-Theory-- just as all possible positions in space exist together, General Relativity indicates that all possible positions in time exist together. Rather than talking about 3-dimensional Space and a completely different thing called Time, General Relativity cemented the notion that our universe seems to be made up of a 4-dimensional space-time. This space-time has its own geometry-- a geometry which might seem a bit alien to anyone whose only experience with the field is the plane geometry they learned in high school. Space and time can curve and bend, and it is this strange shape of space-time which account for gravity and motion.
Subsequent developments in physics have piled even more weirdness onto our understanding of how Time works and what Time actually is. All of this, taken together, is why I am still a convinced B-Theorist with regards to Time.
Objections Against the B-Theory
Here are just a few of the objections to the B-Theory which I have seen, along with some commentary for why I don't find them convincing.
ACT and POTENCY as a means of understanding ChangeNeo-Aristotelian Perspectives on Contemporary Science, published in 2018. In the essay, Feser defends A-Theory conceptions of time-- particularly Aristotle's ideas about act and potency-- in light of modern science. He states:
LORENTZIAN RELATIVITY
William Lane Craig often notes that there is another model of Relativity which had originally been developed by Hendrik Lorentz which is empirically equivalent to Einstein's Relativity and which yet posits the existence of a frame of absolute time and space which, he argues, could restore the notion that reality moves along a common universal progression of time. Unfortunately for Dr. Craig, empirical equivalence most certainly does not mean the same thing as "exactly as reasonable." In fact, empirical equivalence doesn't even mean that the theory is plausible.
To illustrate my meaning, imagine someone took Newton's mathematical formalism for Gravity but was puzzled by the idea that two objects could be attracted to one another despite being at a distance. So, this well-meaning thinker now posits that the cause of this attraction is the presence of invisible, intangible, and wholly undetectable fairies which are actively pushing the two objects together. This Fairy Theory of Gravity is completely empirically equivalent to Newtonian Gravity. Does that make it just as reasonable? Certainly not.
This is precisely analogous to Lorentzian Relativity. The only thing which Lorentzian Relativity adds over against Einsteinian is the notion that there exists some inertial reference frame which is correct while all of the others are only illusory. Except that this Lorentzian aetherframe is in an even worse logical position than the gravity fairies were. It's not just the case that the aetherframe is wholly undetectable; the aetherframe is entirely indistinguishable from any other frame. Even if someone could somehow detect this aetherframe, there is nothing which would make that frame "correct" and all others "incorrect" other than a completely arbitrary label. To say that it is "correct," in such a case, is a totally meaningless distinction.
COSMIC TIME and symmetries of General RelativityDETERMINISM
The nature of the B-Theory seems to entail that some form of Determinism must also be true. Those who are committed to the Libertarian notion of free-will are therefore likely to find B-Theory understandings of Time to be entirely unpalatable.
I am not a Libertarian, with regards to free-will, so this objection doesn't really exert much power, in my eyes. However, I can certainly understand how it might be much more concerning to other people.
PSYCHOLOGICAL EXPERIENCE of Temporal Passage
This is, by far, the most difficult challenge to the B-Theory to address and the biggest stumbling block which most people have when considering the idea. The arguments from physics are well understood but far removed from our common experience. In contrast, psychological experience is not well understood and is the entire foundation of our common experience. Thus, the basic question goes, "If all moments of time exist together, then why is it that we seem to only experience them one at a time and in a constant, sequential order?"
I will not lie. I do not have a complete and scientifically well-supported answer to this question. I do have some thoughts on the matter, and I do believe that there is a path towards reconciling the B-Theory with the psychological experience of temporal passage. Though I'm sure we will get into this more as the thread progresses, for now I will simply note that my particular ideas towards reconciliation build upon the memories and stimuli available to a psychological state at particular moments in time.
Let's Talk It Out!
I know that's quite a lot of information to take in, while still not being anywhere near completely explanatory. When I was asked to write a post on my views about Time, I knew it was going to be a bit daunting. But I'm looking forward to discussing it! Whether or not you agree with my position, I hope everyone enjoys this thread.
Despite being something which nearly everyone appeals to throughout the entirety of his thinking life, the idea of Time is not very easily understood. Most people have never even thought to ask the question, "What is time?" let alone put serious effort into seeking an answer. Those who have quickly realize that the topic is far more complex than they'd thought.
When the average person thinks about time, they have this sense of something flowing ever forward. The past is behind us and gone. The future is ahead of us and unwritten. The present is the only thing that is real and it constantly slinks away into the past.
This sort of description is the basis for Tensed theories of Time-- sometimes also referred to as "Temporal Becoming" or "A-Theory." While there are specific models within the overarching group of Tensed Theories which have slightly different implications, the main idea is this notion that the future is not a thing which really exists. We can speculate about the possibility and potential of what may happen in the future; but those potentialities are not real, existing events until they are instantiated in the present.
In contrast, we can look at Tenseless theories of Time, sometimes called "Block Universe" or "B-Theory." Certainly far less intuitive, Tenseless models treat past, present, and future all as being equally real. The future is set in stone and though we seem to only experience it sequentially, one moment at a time, the things that will happen tomorrow are no less real than the things which are happening right now and the things which happened yesterday.
Given the fact that the A-Theory accords so well with our common experience, one might ask why anyone would ever ascribe to the B-Theory.
A Bit of Autobiography
My own journey in this regard may be somewhat unique. I was born into an Evangelical Christian home with devout parents, so I grew up with a very active religious education. One of the things which I had been taught, as is common within Christian theology, is that God is omniscient and all-knowing. God knows the entire story for everything, including all of the past, present, and future. In my mind, having been raised with this notion of omniscience since before I was even able to speak, it only made sense that if God knows the future then the future must be something real, something which exists and therefore can be known. While I certainly had the same experiential notion of time's flow that everyone has, it just seemed obvious to me that the future must already be fixed in some way. If God knows what I will do in the future, then it is logically impossible for me to do otherwise.
Whenever I talked to other people about these ideas, I found that they were really attached to the idea that the future is not set in stone and that the common-experience version of time must be true. However, I found my questions were very often hand-waived away with glib responses about "free-will" or "mystery" or other things which really didn't satisfy me. To be fair, I was just a little kid, so the only people I talked to about this were my parents, my friends, and my Sunday School teachers. It's hardly surprising that none of them were able to give me sophisticated answers to my questions.
As I got older, I started to have a boyish fascination with science. I loved my Math and Science classes in grade school and any time I could, when doing a History report, I chose to focus on a famous scientist. One of my particular heroes, at that time, was Einstein and I remember doing a massive report on him. We were supposed to come up with a 5-minute report to present in front of the whole class. After 15 minutes, the teacher cut me off and said we had to move on to other students. While I was still very young and didn't have the tools to completely understand what I was reading, I remember being absolutely ecstatic when discovering Relativity. It was the first time I had ever seen an explicitly tenseless idea of time laid out anywhere and it seemed like every weird thought I had conceived about how time works was suddenly being confirmed by science.
When I eventually started learning algebra, geometry, calculus, and physics, I began to realize that there were a lot of implications from Relativity on Time which I had not yet considered. Learning about these only bolstered my feeling that Time couldn't be as simple as the naive, common-experience approach to which my friends had all seemed so thoroughly attached.
Now that I am no longer a theist, obviously God's omniscience is no longer one of the reasons that I am convinced of the B-Theory. However, I find the evidence from philosophy, Special Relativity, General Relativity, and even more obscure areas of science to be so compelling that I remain a committed B-Theorist, to this day.
Relativity and Time
If you are unfamiliar with the science, you may now be wondering what Einstein's Relativity has to do with how we understand Time.
On the common-experience idea of time, we have this notion that the passage of time is the same for everyone and everything. If one second passes for me, then one second also passes for you and for a tree outside and for the Sun and for everything in the universe. Because of this, we have this notion that two different events can happen at exactly the same moment in time; that is to say, two different events can be simultaneous with one another.
In 1905, a young Albert Einstein published a paper describing what we now call "Special Relativity." I won't get into the specifics here, for the sake of brevity, but there are tons of amazing resources available on the Internet for anyone interested in learning precisely how Einstein came to his conclusions, and it is actually far easier to understand that reasoning than most people seem to believe. If you can handle some very basic, grade-school level algebra, you have all the math you need to understand the basics of Special Relativity. Long story short, Einstein's Special Relativity completely overturned these common-experience ideas about how time passes and whether two events happen simultaneously. The very strange truth of the matter is that time can pass differently for different observers depending upon how quickly they are in motion relative to one another. Because of this, two events which appear to be simultaneous for one observer might not be simultaneous to others seeing the same thing.
There was a significant catch, however. Einstein realized that his mathematical formulation of these phenomena only worked when discussing objects which are moving at constant velocities. The mathematics breaks down when we try to consider things which are accelerating or decelerating or not simply moving in straight lines. This is why we call it "Special Relativity," because the theory only applies to special cases.
Though it took Einstein more than a decade, lots of help from his friends, and much, much more complicated mathematics, in 1916 he managed to publish another paper which generalized his ideas about relativity so that they applied even in cases of acceleration, deceleration, and non-linear motion. The implications of this work on Time were even weirder than those of Special Relativity. On General Relativity, Time is a dimension of positional measure, very similarly to the way the three dimensions of space are. This alone implies the B-Theory-- just as all possible positions in space exist together, General Relativity indicates that all possible positions in time exist together. Rather than talking about 3-dimensional Space and a completely different thing called Time, General Relativity cemented the notion that our universe seems to be made up of a 4-dimensional space-time. This space-time has its own geometry-- a geometry which might seem a bit alien to anyone whose only experience with the field is the plane geometry they learned in high school. Space and time can curve and bend, and it is this strange shape of space-time which account for gravity and motion.
Subsequent developments in physics have piled even more weirdness onto our understanding of how Time works and what Time actually is. All of this, taken together, is why I am still a convinced B-Theorist with regards to Time.
Objections Against the B-Theory
Here are just a few of the objections to the B-Theory which I have seen, along with some commentary for why I don't find them convincing.
ACT and POTENCY as a means of understanding ChangeNeo-Aristotelian Perspectives on Contemporary Science, published in 2018. In the essay, Feser defends A-Theory conceptions of time-- particularly Aristotle's ideas about act and potency-- in light of modern science. He states:
The way that relativity is supposed to pose a challenge to that theory is not by showing that it is mistaken as an analysis of the preconditions of change and temporal passage, but by showing that there are no such things as change and temporal passage in the first place.
William Lane Craig often notes that there is another model of Relativity which had originally been developed by Hendrik Lorentz which is empirically equivalent to Einstein's Relativity and which yet posits the existence of a frame of absolute time and space which, he argues, could restore the notion that reality moves along a common universal progression of time. Unfortunately for Dr. Craig, empirical equivalence most certainly does not mean the same thing as "exactly as reasonable." In fact, empirical equivalence doesn't even mean that the theory is plausible.
To illustrate my meaning, imagine someone took Newton's mathematical formalism for Gravity but was puzzled by the idea that two objects could be attracted to one another despite being at a distance. So, this well-meaning thinker now posits that the cause of this attraction is the presence of invisible, intangible, and wholly undetectable fairies which are actively pushing the two objects together. This Fairy Theory of Gravity is completely empirically equivalent to Newtonian Gravity. Does that make it just as reasonable? Certainly not.
This is precisely analogous to Lorentzian Relativity. The only thing which Lorentzian Relativity adds over against Einsteinian is the notion that there exists some inertial reference frame which is correct while all of the others are only illusory. Except that this Lorentzian aetherframe is in an even worse logical position than the gravity fairies were. It's not just the case that the aetherframe is wholly undetectable; the aetherframe is entirely indistinguishable from any other frame. Even if someone could somehow detect this aetherframe, there is nothing which would make that frame "correct" and all others "incorrect" other than a completely arbitrary label. To say that it is "correct," in such a case, is a totally meaningless distinction.
COSMIC TIME and symmetries of General RelativityDETERMINISM
The nature of the B-Theory seems to entail that some form of Determinism must also be true. Those who are committed to the Libertarian notion of free-will are therefore likely to find B-Theory understandings of Time to be entirely unpalatable.
I am not a Libertarian, with regards to free-will, so this objection doesn't really exert much power, in my eyes. However, I can certainly understand how it might be much more concerning to other people.
PSYCHOLOGICAL EXPERIENCE of Temporal Passage
This is, by far, the most difficult challenge to the B-Theory to address and the biggest stumbling block which most people have when considering the idea. The arguments from physics are well understood but far removed from our common experience. In contrast, psychological experience is not well understood and is the entire foundation of our common experience. Thus, the basic question goes, "If all moments of time exist together, then why is it that we seem to only experience them one at a time and in a constant, sequential order?"
I will not lie. I do not have a complete and scientifically well-supported answer to this question. I do have some thoughts on the matter, and I do believe that there is a path towards reconciling the B-Theory with the psychological experience of temporal passage. Though I'm sure we will get into this more as the thread progresses, for now I will simply note that my particular ideas towards reconciliation build upon the memories and stimuli available to a psychological state at particular moments in time.
Let's Talk It Out!
I know that's quite a lot of information to take in, while still not being anywhere near completely explanatory. When I was asked to write a post on my views about Time, I knew it was going to be a bit daunting. But I'm looking forward to discussing it! Whether or not you agree with my position, I hope everyone enjoys this thread.
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