Can time be understood conceptually without experiencing it? I think Wittgenstein said that most concepts cannot be understood unless we have an image or an experience of it, but how true is this? Cannot time be described in a conceptual way that could be understood by a being that hasn't ever experienced time theoretically? Is there any thought experiment that was done on this to allow us to get some insights on this?
To get a really good answer you should explain what you mean by "understand", do you mean be able to construct a mathematical model and make predictions? or maybe get such an intuitive feel for it that you can make predictions in your head, without having to write down equations?
In any case, physicists and mathematicians regularly deal with higher dimensional spaces (and even infinite ones), and they have tricks to deal with them that give them enough insight to prove things about them. If you can call that "understanding", then I'd say the answer is yes, we can reasonably understand higher dimensional spaces without experiencing them, so I see no reason a sufficiently advanced species couldn't understand time without experiencing it.
Ill-formed question: understanding already presupposes the experience of time.
Understanding essentially means making inferences with concepts (e.g. understanding how vaccines work means inferring that after taking a jab a series of causal mechanisms are triggered, and the final fact in the sequence would be the production of antibodies).
So, ponendo ponens, if an entity cannot experience time, it is probably that it would not have the capabilities to understand (not only time: she would understand nothing).
Tollendo tollens, if she understands (not specifically time, but something), then she has already experienced time.
Good question. In general reletivity time exists as a conept ( as it exists in the eternal block universe). But you need the experience of time first to give meaning to the concept. Everything around us changes irreversibly and this gives us a notion of things moving trough time (and space which already shows that the two are connected).
The notion can be objectified and as such obtain an objective existence. As such it already existed before creatures experiencing time.
There are two objective notions of time. It can exist as separate points (or a continuum) or as the motion of points over these points. For the block universe the first concept is used. All of spacetime exists without matter or energy in it. But mass and energy do determine the shape of this block universe.
The other notion is the notion of time that is derived from the from motion. Only intervals of time are important in that notion.
Without the points there is no interval but there can be a point without the interval. This only goes to show that there can't be a point in time that is the first one because such a point can't give rise to motion in time as for motion different points must exist (there has to be a force before a particle gets motion, i.e. there has to exist a prior time to time zero). The zero time cannot exist on it's own.
But all this aside.
Time can exist on it's own. Subjective time can also exist on it's own (when you dream, for example). But they need each other to exist on their own. So if there are no more creatures to experience time or to even objectify it (like we do) it will stop to exist. Even objective time, though you can imagine it to exist for ever.
Relativity shows time can't be fully understood from our experiences, because they don't include high gravity or speeds a significant fraction of that of light.
Given things like physics with two time dimensions, and time stopping at the edge of a blackhole from the rest-frame of an observer outside, our intuitions are not reliable. Time without a theory of quantum-gravity is still deeply mysterious.
If there is one thing Wittgenstein did not trust to reveal truths, it was introspection. Time as a 'quale' he would have given very short shrift to.
"For what is time? Who can easily and briefly explain it? Who even in thought can comprehend it, even to the pronouncing of a word concerning it? But what in speaking do we refer to more familiarly and knowingly than time? And certainly we understand when we speak of it; we understand also when we hear it spoken of by another. What, then, is time? If no one asks me, I know; if I wish to explain to him who asks, I know not." -St. Augustine: Confessions, BOOK XI, CHAPTER XIII,
Discussions of time on here:
How can time have a beginning when a beginning needs time? (time can neither begin nor be infinite)
Is the human mind capable of distinguishing between time running forward and time runing backward? (time is the spreading out of information)
Any good theories on the nature of time in which time is not fundamental? (time as emergent)
Is perception of time completely subjective? (time as an embodied experience)
Yes. Take a person who understands time from experience, and analyse the structure of their brain down to the position of every atom. Now create a new brain exactly identical to the first and assemble it in a fraction of a second. At the moment of its creation, the new brain understands time without ever having experienced it. The detailed description of the structure of the brain's own storage of concepts constitutes a description of time "described in a conceptual way". If it can thus be expressed in one 'language', it can no doubt be expressed in many other ways.
The problem, as others say, is what does 'understanding' mean, and how do you read a 'conceptual description' without there being time in which to do so?
Can these beings understand graph theory and formal logic?
You might argue that this does not constitute true understanding. I would counter by saying that I reason about parallel universes when I use git or watch a Marvel movie despite not having experienced one firsthand. I have a good understanding of 2d geometry despite never having experienced flatland. Additionally, my understanding of time gained through firsthand experience is only approximate.