“The distinction between the past, present, and future is only a stubbornly-persistent illusion.”

Albert Einstein

Arguments against contraception and abortion require a correct understanding of the nature of time. Indeed, any argument which relates to future people relies upon an understanding of time; this includes ecological arguments (“we have a responsibility to preserve the environment for future generations”), financial arguments (“we need to avoid saddling future generations with government debt”), and many others. A correct understanding of time is essential to moral reasoning. Unfortunately, provably-wrong beliefs about time are extremely prevalent, in both the Western world and beyond, and on all sides of the political spectrum. Misinformation about time has convinced the vast majority of living people–including many of the highly-educated–into believing an idea that is as wrong (and as provably wrong) as the claim that the Earth is flat. In the same way that misinformation about climate change and vaccination is dangerous, so too is misinformation about time.

Before we move further, we need to dispel lies and ignorance about time. To begin, we’ll examine how people grow into adulthood, and study the dispulsion of another sort of ignorance.

Object permanence is a critical milestone in a child’s development: during the second year of life, a child begins to realize that objects (and, indeed, people) can exist even when he or she does not directly observe them. A child without object permanence will be flummoxed by the game of peek-a-boo, not realizing that Mama still exists even when she covers her face with her hands. To a child without object permanence, items and people come into existence the moment they are observed (seen, heard, touched, etc.), and vanish from existence the moment they are no longer observed. Placing a blanket over a toy magically destroys it, and removing the blanket creates an identical toy anew. To an infant, closing one’s eyes seems the ideal hiding strategy.

Closing one’s eyes to hide? Rather clueless, isn’t it?

Clueless, yes– but cluelessness is in fashion. Just as infants close their eyes to hide from barking dogs, so do proponents of contraception and abortion close their own eyes to hide from a simple but consequential truth: in the same sense that people and objects in faraway places exist when we can’t see them, so do people and objects in the far future and distant past exist. A man who lives to the North or South of you (relative to your conception of “here”) is just as real as you are. A woman who lives ten thousand years in the future or lived ten thousand years in the past (relative to your conception of “now”) is just as real as you are. To the extent that you can affect the lives of people in other places and times, you have certain minimal responsibilities towards them.

Typically, those responsibilities include “do not commit murder”.

Time permanence is a skill, and just as important as object permanence (which might itself be called “space permanence”, since an object’s observability generally depends on its position in space relative to the observer, as well as the spatial positions of any obscuring objects). The person who subscribes to “Presentism”, or the philosophical belief that only the present time is real, is just as mentally immature as the child who thinks that Mama is real only when she is not hiding her face behind her hands in a game of peek-a-boo.

Let’s grow up, shall we?

What, then, is time? As a word, “time” is unusual. Typically, the more complex a concept a word or phrase refers to, the harder it is to translate between languages. It’s quite easy to translate “I pet dogs” from English to Russian, but much more difficult to translate “Ontogeny recapitulates phylogeny”. This is because “dog” is a simpler noun than “ontogeny”, and “to pet” is a simpler verb than “to recapitulate”. However, “time” is a special word: the concept it refers to is extremely complex and non-intuitive, but translating it is very easy, and in most cases, a word-to-word substitution is acceptable, even between radically-different languages: simply substitute the English “time” with the Russian “время”, apply a few rules for conjugation, and you’re done.

Ray Cummings wrote, rather tongue-in-cheek: “Time is what keeps everything from happening at once”. Cummings was not a physicist or a scientist; he was a fiction author, one of those “creative types”. Yet despite this, he stumbled upon a very deep truth about time: it is a dimension that allows events, or rather specific states-of-the-world, to exist without conflicting with each other. One might similarly say: “space is what keeps everything from existing in one place”. Without dimensions of space, objects and people that we consider to be separated by distance would all be crammed into an infinitely-small point, or singularity. Without the dimension of time, states-of-the-world (the world in which a specific person is a child and the world in which that same person is an adult, for instance) would all be crammed into the same infinitely-short interval. Certainly, we’re fortunate that space and time both exist – things would be a bit cramped otherwise. We’re on to something here.

Time is a physical dimension. Our universe is provably four-dimensional at the very least (more dimensions may exist, but only four are proven to exist at the macroscopic level). Three of these dimensions are spatial, and one (time) is temporal. Critically, all four dimensions of the universe are entwined in a four-dimensional “space-time”, as postulated by Einstein’s theory of special relativity. This scientific theory has been tested and confirmed repeatedly, and the scientific consensus is that it is proven – as proven as the law of gravity. A violation of special relativity would be as shocking as a violation of the theory of gravity, as shocking as if gravity suddenly began to push instead of pull, causing apples to “fall” upwards into the sky as they ripened on the branches of trees. We will not present the mathematical proofs of special relativity here, nor will we lay out all the many experiments which have confirmed it. Anyone unfamiliar with special relativity ought indeed to study such proofs and experiments, but this resource is not a textbook on mathematics, nor physics. Rather, we will treat special relativity as a proven fact (which it indeed is), and explore several of its consequences:

1. Invariance Of The Speed Of Light:

The speed of light (given as “c“, in the famous E=MC^2) is constant in all reference frames. If someone is throwing tennis balls towards you at speed X (for example, 40 kilometers per hour), and you run directly towards this person at speed Y (for example, 10 kilometers per hour), then you will observe the tennis balls approaching you at X+Y = 50 kilometers per hour. Similarly, if you run directly away from the tennis-ball-thrower, you will observe the tennis balls approaching you at X-Y = 30 kilometers per hour.

Light is not like this.

In a vacuum, if someone shines a light at you, you will always observe the photons of light to be approaching you at c, or approximately 299,792 kilometers per second. No matter how fast you move towards the source of the light (or it towards you), this speed will not increase, not even slightly. No matter how fast you move away from the source of the light (or it away from you), this speed will not decrease, not even slightly.

2. Orthogonality Of Space & Time:

Spatial dimensions are orthogonal to each other–that is, they meet at angles of exactly 90 degrees. For example, consider a two-dimensional coordinate system that uses “North-South” as one dimension and “East-West” as the second dimension. In this coordinate system, a line that runs perfectly North-South will always cross a line that runs perfectly East-West at a right angle; in fact, all N-S lines will always cross all E-W lines at 90 degree angles. If we extend our two-dimensional coordinate system to include altitude (adding an “Up-Down” dimension), we will now have three dimensions, all of which are orthogonal to each other: lines running perfectly Up-Down, North-South, and East-West will always cross each other at right angles. Time is the fourth dimension; we can call it the “Past-Future” dimension, and add it to our existing three spatial dimensions, resulting in four-dimensional space-time. Mountains of scientific research indicate that time is orthogonal to the spatial dimensions. Thus, we can say that “Up-Down”, “North-South”, “East-West”, and “Past-Future” are all orthogonal, and that any line drawn parallel to the dimensional axis in any one dimension will always intersect any line drawn parallel to the dimensional axis in any other dimension to form a right angle.

3. Relativity Of Time:

We have established that (1) the speed of light is constant, and (2) the three dimensions of space and one dimension of time are all orthogonal to each other. When we consider that the speed of light, c, is a sort of “universal speed limit”, something interesting occurs to us: movement in one dimension necessarily places an upper limit on movement in another dimension.

To understand this, let’s return to our simplified two-dimensional world, with a North-South dimension and an East-West dimension. Imagine that we have a car which always moves at a speed of exactly 150 km/h. Just as the speed of light c is constant, so is the speed of our car. If we get in our car and drive due North, we are moving 150 km/h along the North-South axis; we’re moving Northward at 150 km/h. Similarly, we can instead drive our car due East; in that case, we’re moving at 150 km/h Eastward along the East-West axis. Fair enough. But what happens if we want to drive both North and East at the same time? We can obviously do that; we drive our car in a North-Easterly direction, 45 degrees North of due East (or, equivalently, 45 degrees East of due North). Our car is now traveling Northeast at 150 km/h. We can use trigonometry to determine that our car is moving North at (150km/h) * (2^(1/2)) / (2), or approximately 106 km/h. Our car is also moving East at approximately 106 km/h. It is intuitively obvious that a car that always drives 150 km/h can’t simultaneously move East at 150 km/h and North at 150 km/h; moving Northeast requires striking a balance between the two directions, sacrificing some Northerly speed in exchange for Easterly speed, and vice versa. In essence, our speed of 150 km/h is like a fixed budget; we can choose different ways to spend it–for example, we could instead choose to drive almost due North, just a single degree East of due North. Yet every possible direction of travel involves a compromise between the speed of North-South travel and the speed of East-West travel.

What happens when we add a third dimension, and imagine that our car can also fly straight up or straight down? We still have the same budget of 150 km/h; now we’re just splitting it three ways, rather than two. We can “spend” some of our budget to increase our upward speed, but that involves sacrificing some North-South speed, or East-West speed, or both.

It’s time to add the fourth dimension, but before we do so, let’s discard the 150 km/h speed limit of our example, and replace it with c, the cosmic speed limit. c is not any more “special” than 150 km/h; it’s a number just like any other. To be precise, c = 299,792 km/s (note that we’re switching from kilometers-per-hour to kilometers-per-second; put another way, c = 1,080,000,000 km/h). With the speed of our car upgraded roughly ten million times, let’s add the fourth dimension: time. As time is orthogonal to the other dimensions, then just as faster North-South movement means slower East-West movement, faster movement through space in any direction means slower movement through time. Suppose that our car is driving due North along a road, and a gentleman stands at a bus stop along that road. As the car drives by at speed, the gentleman at the bus stop will observe that clocks in the car seem to be running slowly; the car’s Northerly movement in space slows down its “futurely” movement in time. The faster the car moves North, the slower it (and its occupants and clocks) move into the future. If the car drives past at 0.1c (10% of the speed of light; approximately 108,000,000 kilometers per hour), then its clocks will run roughly 0.5% slow, relative to a clock held by the patient fellow at the bus stop – missing about one second every three minutes. If the car drives past at 0.5c (50% the speed of light; approximately 540,000,000 km/h), then its time will run still slower; about 13% slow, missing nearly 8 seconds every minute. At 0.9c, time in the car passes only 44% as fast as it does for the man at the bus stop. If the driver of the car really steps on the gas and reaches the speed c itself, then all of the car’s movement budget is consumed by movement in the Northerly spatial dimension, and it cannot move through time at all; the man at the bus stop will observe time to have completely stopped in the car as it passes by, while the car driver will consider his time to be running normally, while observing that the bus stop gentleman’s time is moving infinitely quickly. Here we see that a finite speed of light and the orthogonality of dimensions imply that the speed of time is relative. This has been demonstrated experimentally in many instances. For example, two matched and highly-accurate atomic clocks were synchronized, and then one clock was loaded onto an aircraft, flown at high speed, and finally returned to the laboratory housing its stationary partner. When compared, the clocks no longer matched; the clock that had flown was slow relative to the stationary clock. An ignorant person–someone who fundamentally fails to understand the nature of time–would look at mismatched clocks and assume that one or both of them had malfunctioned. In fact, both clocks were correct; the clock flown on an airplane wasn’t “running slow”; it was measuring time perfectly. Time itself had slowed down during the flight. The clocks didn’t disagree because they operated differently; they disagreed because time itself flowed at different speeds.

4. Relativity Of Simultaneity & Sequence:      

It can be shown that, just as the rate at which time passes can be different in different reference frames (for example, in the reference frame of the car versus the reference frame of the bus stop), so too can the order of events. Suppose that a church bell rings at exactly noon, 12:00 local time, in Berlin, Germany. On the same day, a church bell approximately 1,800 km East in Moscow, Россия rings at exactly 13:00 local time. As Moscow is exactly one hour ahead of Germany, then from the reference frame of the Earth (and, hence, the reference frame of anyone standing relatively still on Earth), these bells rang simultaneously. True, they rang at different local times, but time zones are merely a convenient human invention; they don’t affect simultaneity in any deep way. All observers at rest relative to Moscow and Berlin–for example, observers in Moscow, or Berlin, or Paris, etc.–would agree that the bells rang simultaneously. However, an observer traveling rapidly Eastward from Berlin to Moscow would observe the Moscow church bell to have rung first; an observer traveling rapidly Westward from Moscow to Berlin would in turn consider the Berlin bell to have rung first. So, what happened? Did the Moscow bell ring first, or did the Berlin bell ring first, or did the bells indeed ring simultaneously? The reality is that each of the three interpretations is equally valid; no observer’s perspective is “better” or “worse” than any other perspective. There is no absolute sense of sequence or simultaneity for events separated in space.

If you stand to the left of a chair, the chair is to your right; if your lover stands to the right of the same chair, the chair is to his left. So, where is the chair located – to the right, or to the left? The answer, of course, is “it depends on the position of the observer”. Descriptions such as “to the right” and “to the left” are relative. So are terms such as “before”, “after”, “at the same time”, “in the future”, and “in the past”. Your right is someone else’s left; your future is someone else’s past.

5. No Privileged Reference Frames:      

The laws of physics are identical in all inertial reference frames (that is, in all reference frames that are not accelerating, i.e. not changing their speed and/or direction). No inertial reference frame is “privileged” (more correct) or “de-privileged” (less correct) relative to any other. Physical laws are the same over all space and all time; a self-contained experiment run today will produce the same results as one run ten thousand years in the past or ten thousand years in the future, and will produce the same results no matter where on Earth or in the Universe it is run. This suggests that there is nothing special about an individual’s concept of “here” or “now” (words we use to refer to particular points in space and time, respectively – specifically, those points in space and time that we happen to occupy). An individual’s “here” and “now” may be important to them, but in a physical sense, no individual’s “here” or “now” take primacy over other possible locations or times.

6. Ergodicity As Further Evidence Of Time-As-A-Dimension:

Ergodicity is central to statistical mechanics, the field uniting the microscopic and rarely-observable (or, at least, rarely-conveniently-observable) world of quantum mechanics with the macroscopic world of thermodynamics. Put simply, the Ergodic Postulate states that the time-average and ensemble-average of a system are statistically indistinguishable. “Ensemble averaging” refers to an average taken by duplicating a system and observing multiple copies of it.

To understand ergodicity, imagine that you have obtained a coin which, when flipped, has an exactly 50% chance of landing “heads”, and similarly a 50% chance of landing “tails”. You do not know this, and in order to investigate the properties of the coin, you plan a series of experiments. You will need multiple data points; flipping a coin once and having it land “heads” does not prove that the coin will so land 100% of the time. Large sample sizes are key to understanding statistical behavior.

Time Average: In one series of experiments, you flip the coin repeatedly, recording the outcome with each flip. As you continue to flip the coin and gather more data, you will come to the conclusion that the coin is “fair”, landing “heads” half the time, and “tails” the remaining half of the time. You have performed a time average: each experiment occurred during a different time interval, but in the same place.

Ensemble Average: In a second series of experiments, you obtain a large quantity of coins, all identical to the original coin, and dump them from bucket as you stand on the roof of a tall building. Once you descend, you observe the state of each of the coins, and find that half have landed “heads” and half “tails”. You have performed an ensemble average: every coin was effectively flipped at the same time, but the coins have landed in different positions across space. This is, in effect, an average-across-space.

Ergodicity implies that both experiments – the average-across-time experiment and the average-across-space experiment – should be identical in their results, within expected deviations due to random chance. In other words, as the number of coin flips (in the time-average experiment) and the number of coins dumped off the roof of a building (in the ensemble-average experiment) trend towards infinity, the results of the two methods will converge, becoming identical. Ergodicity therefore gives further evidence that time and space are both physical dimensions: averaging across one dimension is equivalent to averaging across another.

7. Two Pairs: Time and Space; Matter and Energy

Einstein’s famous E=MC^2 is a startling mathematical claim: that energy and mass are equivalent, and that matter is merely a condensed form of energy. The atom bomb is a demonstration of just how much energy is contained in a relatively small amount of matter.

Just as Einstein demonstrated the equivalency of matter and energy, so did he demonstrate the equivalency of space and time. These equivalencies have a curious consequence: units used to measure mass (such as kilograms) can be used to measure energy, and units used to measure energy (such as calories) can be used to measure mass. Similarly, units used to measure time (such as seconds) can be used to measure distance, and units used to measure distance (such as kilometers) can be used to measure time. In particular:

  • One kilogram (roughly 2.1 pounds) of energy is 21,500,000,000 kilocalories (“food calories”), or roughly 1,200 times the energy released by the Hiroshima atomic bomb. Similarly, this is the energy that would be released by burning 2.6 trillion liters of gasoline, enough to satisfy American gasoline demand for two years.
  • One kilocalorie (“food calorie”) (roughly 4.2 joules) of mass is 0.000000000047 grams, or roughly 1/100 the weight of a human blood cell, or 1/1,000,000,000 the weight of a grain of rice.
  • One second of distance is 300,000 kilometers (186,000 miles), or roughly 69 times the distance from New York to Los Angeles.
  • One kilometer of time is approximately 0.000003 seconds.

We do not typically measure energy in kilograms, because a kilogram is a tremendously large amount of energy. We do not typically measure weight in calories, because a calories is a tremendously small amount of weight. We do not typically measure distance in seconds, because a second is a tremendously long distance. We do not typically measure time in kilometers, because a kilometer is a tremendously short interval of time. However, this is merely for the sake of convenience; it’s inconvenient to write dozens of zeroes or use scientific (“exponential”) notation to express very large or very small numbers in daily life. There is absolutely nothing technically wrong with using units in the ways shown above, in the same sense that there’s nothing technically wrong in measuring your child’s height in miles: you’ll just be writing a lot of zeroes. The fact that we can convert between measures of time and measures of distance should further drive home the fact that time and space are equivalent.

8. Resources On Understanding Time for Laypeople:

The following two short films may be helpful in understanding the nature of time. None of the individuals appearing in these films–nor any individuals or entities involved in the distribution of said films–have endorsed this resource. The following films are reproduced without the permission or knowledge of their authors, publishers, or rights-holders. Such individuals and entities therefore bear no responsibility for the contents of this resource. Do not pester them.

Resource 1: Greene, Brian. “The Illusion Of Time”. NOVA: Fabric of the Cosmos, Season #38, Episode #17. Recorded 2011-11-09.

Resource 2: Rovelli, Carlo. “The Physics & Philosophy Of Time”. Speech at the Royal Institution, Albemarle Street, London, 2018-06-13.

9. Your Responsibilities:

The reality of time-as-a-dimension implies that, if one has responsibilities towards people in different places (i.e. towards people who occupy different locations in space), one also has responsibilities towards people in different times. People living in the future and the past are, after all, just as real as you are–in the same sense that people living in other places are just as real as you are. Examine the following two statements:

Statement 1: “Killing foreigners is acceptable – it’s fine to eliminate the lives of far-away people, because the lives of people living nearby in space are more important.”

Statement 2: “Birth control and abortion are acceptable – it’s fine to eliminate the lives of future people, because the lives of already-living people are more important.”

The first statement is an example of space-chauvinism: the idea that our personal conception of “here” is more real or valid than someone else’s “here”, and that the lives of people separated from us by space are somehow less important.

The second statement is an example of time-chauvinism: the idea that our personal conception of “now” is more real or valid than someone else’s “now”, and that the lives of people separated from us by time are somehow less important.

Of course, some people do agree with the first statement; some people do think that the lives of far-away people have little value, or no value at all, or even negative value. Some people do think that those living in other countries or on other continents matter less, or matter not at all, or are better dead than alive. Indeed, the idea “the lives of people near to me are more valuable than the lives of people separated in space” underlies ultranationalism. Racial differences in intelligence, appearance, resistance to disease, and similar primarily result from differences in physical location (people whose ancestors lived in hot climates will typically have darker skin than those whose ancestors lived in cold climates, for instance). In that sense, Statement 1 is also a cornerstone of racism.

Proponents of contraception and abortion are, in effect, in agreement with both Statement 1 and Statement 2; the equivalency of space and time as physical dimensions implies that Statement 1 and Statement 2 are also equivalent. Those who value their own comfort enough to destroy the lives of future people are in the same boat as those who value their own comfort enough to destroy the lives of foreigners.

Watch the company you keep.