Argthtjtr

Pretty much every book out there which claims to teach the readers to appreciate classical music, has significant amount of theory in it. Ex: What to listen for in Music by Aaron Copland. Is it not possible to enjoy a classical piece without having any theoretical knowledge? If it is possible, kindly point to correct resources which helps in achieving the goal.

Of course it is. And most people do.

And, while any piece more extended than a simple song probably does involve a 'journey' of some kind, there's no need to invent a storyline.

Is it possible to enjoy driving a car without understanding how the gearbox works? Watching t.v. without understanding the electronics involved?

Yes, of course! In fact, once theory is studied and understood, most music is listened to and appreciated in other ways. Not better or worse, just different.

Think about it: if music was only appreciated if the listener was versed in theory, it would have probably died the death well before now.

A lot of my students have commented that they don't listen to music in the same way, once they understand the tricks used and the theory involved. Which can be detrimental, as they then tend to analyse it more, delving deeper into it, to different layers. But that's not necessarily good or bad as far as listening and appreciating goes, just different.

This may get closed as 'how does a layman understand a piece' is very subjective. Take ten people who've listened to a piece of music, and there will likely be ten different reactions, interpretations, or whatever you want to call it, that the music will have given them. O.k., a minor piece may(?) give a sad feeling , but go deeper, and it could be interpreted as nostalgic, sorrowful, serious, tear-jerking, or lots of other emotional effects. Then you'll get the ones who liked the Tierce de Picardie at the end, or the way it modulated in the middle, or the way the staccato part came over. Get the idea?

Yes, it is. They might probably say this is a opinion based question. But everyone who has ever heard some classical music as a baby will confirm that this music is in his mind and his soul like he drunk the milk of his mothers breast.

The adaption to classical music is like the learning of a language, if you've learnt it as a child you will understand it without grammar and theory. But later it will be more difficult like learning a foreign language than the mother language. Theory could be a good help to make it easier but more important are the elements of what you got when you was brought up.

Is it possible to fully enjoy a classical music piece without knowing
the theory behind it? If one should know music theory to enjoy a
piece, was/is classical music for aristocrats? How would layman
understand a piece?

So to answer your question: it is not only possible, it would be quite ordinary that one could understands and enjoy classical music - if he has been adapted to it or if he really wants to listen to it.

Sure. Not bothering about music theory is a valid shortcut to thoroughly engaging with classical music. Like most shortcuts, it actually tends to take quite longer to arrive at any desired destination but if making progress is not on your agenda that may not matter to you.