Also, if time does exist, doesn’t there have to be a definable beginning or end? Otherwise it’s just infinity which to me suggests the absense of time.
I partially read “The Discoverers” by Daniel Boorstin several years ago and he discussed how different societies conceptualized of time and how they kept time. And it has had me wondering ever since. Then I started exploring Zen Buddhism which emphasizes the present moment as the only tangible reality, along with the illusion of the ego, which only furthered my questioning.
EDIT – I am aware that the concept of time is based on the revolution of the Earth and it’s moon. However, that is just how humans conceive of time. That’s not proof of time itself.
EDIT 2 – The explanation of timespace and relativity is the best from an objective point of view. No matter how much I read or watch, it was always a bit hard to grasp but it makes sense in terms of change or entropy. The reality of time being flexible vs the human perception of time being linear and unchangeable gets closer to what I am asking.
EDIT 3 – “Exist” is a tricky word.
In: 7871
A lot of answer here deal with how we measure time or how quantum or relativity determine what the unit of time is. As you say in your edit, that’s lne thing and but you are asking about time itself.
Idon’t usually answer eli5 questions, specially because English is not my native language, but I’m a fan of the subreddit. I scrolled quite a bit and I saw a surprisingly lack of philosophy based answers to your questions(someone mentioned Aristotle’s definition of time).
It’s a bit hard but I’ll advise you to look up what Kant said about time (and space) [Please if someone is reading this and has a philosophy degree which was studied in English,please correct me and my probably wrong terminology, I puzzled third from some articles]
Kant understands time as something a priori. Is part of our sensibility, constitutes, along with space, the way we are able to understand the world. It’s something we put into the world to be able to categorize it. That’s what a priori means, we have it before we start dealing with the world. When we experience objects we put our time frame into them.
This is important as Kant says we cannot have knowledge of the thing itself (noumena), only of the thing as it appears to us (phenomena). For the thing to appear to us we have to ‘cast a net’, which is the time and space, so we can be able to start dealing with what we have catched. This net metaphor is useful to understand the noumena/phenomena, we can only catch what the net is able to retain, and we can never be sure if every bit of reality has been catched, as we are limited beings.
Sorry for the word salad, thinking about Kant in English is quite hard for me. You can look up some articles if you are interested in the philosophical answer to what is time.
Entropy is evidence of why time does in fact exist. Sorta like how wind proves air exists even though we cant see air. If i hold a ball in my hand above the ground gravity gives the ball potential energy. When i let go of the ball potential energy is converted to kinetic energy. All energy seeks to be stable at what we call a resting point. This effect of entropy only happens in one direction though. A star is born, it burns for many millions of years, then it explodes and dies if it is large enough to do so. We do not observe this process going in reverse, or simply stopping completely. The arrow of time always moves forward. Time is relative however and can be slowed down or sped up, but never truly stops or goes backward.
First of all *time* is a word assigned many types of interpretations in many languages through history. Often *times* people are hung up on archaic concepts that doesn’t have any consequence today. Time is not essentially a construct of it’s own, but rather a property and consequence how the universe is constructed with space and energy. A fundamental physical constant of our universe is entropy.
Entropy is a one way ticket dealing with change. We see this established in the second law of thermodynamics as the loss of transfer of energy in a system in one direction.
In this sense, time is a property of certain relationships within space. Unless you are a photon of course, which doesn’t experience time at all.
A bit of a trick question, because you framed it using the words ‘real’ and ‘tangible’, which are not in a 5 year old’s lexicon.
My shot at a ***not***-quantum-physics answer:
“**Real tangible things**” are generally how humans refer to matter. Stuff. Something made out of atoms (or smaller particles).
Some things are real but not tangible.
Phenomena of various types, such as the laws of physics –
* such as time,
* such as matter pulling at other matter (gravity)
These ***are*** real – meaning they are not just in human perception. We can observe and measure them on instruments, and we’re pretty certain they remain that way even when humans are no longer around. If you abandon an island or a moon base, and come back 10 years later, you will find evidence that the laws of physics kept working while you were not there.
To our best knowledge these apply everywhere in the universe – but these phenomena, these rules of physics, are ***not tangible***. You can’t touch or pick up gravity (remembering this is not the quantum physics answer), or time, or the phenomena of day and night that results from a bunch of atoms and photons behaving according to the laws of physics.
Time and gravity are not matter, they are not ***stuff***. They are ***human words*** that describe ***how matter behaves***.
In the case of time, time is simply a way humans describe a medium in which matter can (but doesn’t have to) change. In fewer words but using a word we’d need to explain to a 5 year old, time is a dimension (where our ability to move is restricted to just one direction and to a set speed).
Time and space are part of the same thing.
I know that seems completely ridiculous and new-agey, but it is entirely supported by GR and (afaik) all observed phenomena.
this is literally “if tree falls in the woods”, it’s not actually an answerable question
time is as fundamental as anything, but human understanding of time is and always will only be a human understanding of time, in fact, it’ll only ever be _your_ perception
All the answers here seem to not mention something. We can measure time dilation and have concrete formulas to calculate it. Things like gravity and speed of an object influence how much time it experiences.
This is an interesting and very physics heavy response. Have a read of this https://plato.stanford.edu/entries/time/
Time is an imaginary framework or “mental space” in which our mind references events. It’s not something you can ever “find” or “measure”. Clocks don’t measure time, they simply spin in circles at regular intervals.
It’s like the Celsius scale is an imaginary scale on which temperatures can be placed. Temperatures are real, but the scale on which they exist in a specific order is imaginary and only serves to help us refer to things.
So events exist, things happen, but the time *in which* they happen is just a concept.
Actually, by definition, the past doesn’t exist anymore and the future doesn’t exist yet. In other words, the past and the future don’t exist, but we can remember it and imagine it, meaning that in our mind, time is created through imagination. And while we could say that time isn’t real, it would be like saying the Celsius scale isn’t real: sure, it’s not “real” but a hot temperature will still burn you more than a cold one. But it’s not because of a scale that someone invented. The same way, time may not be real but an apple will still rot. It doesn’t rot because of time, it rots because of bacteria and chemistry, time is just a means to classify those things in a meaningful way.
This is why time only seems to ever move forward: our brain is constantly recording events, so clearly new events come after old events. That’s why time moves forward, and can never move backwards. It’s like the alphabet: it only ever goes in alphabetical order, not because of some hidden physical rule, but because that’s how it was defined.
I just read your post and the top comment and coincidentally this article popped up on my FB newsfeed:
Researchers say time is an illusion. So why are we all obsessed with it?: https://www.npr.org/2022/12/16/1139780043/what-is-time-physics-atomic-clocks-society
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