[Aeris (OP)]

Ok so, around two-ish months ago, I was told by a Cosmologist that what we perceive as matter doesn't actually exist and that the alleged particles that we think it's comprised of are actually "Excitations of fields intrinsic to the universe." At first, I didn't think much of what he said to me. I'd heard far crazier things in science before and considering that the four fundamental forces of the universe already manifest as "fields", it wasn't that hard for me to imagine matter doing the same.

At least, that's how I USED to feel... I've given it some more thought and I'm left with only this to say.

What. The. Actual. HELL?!

Seriously, what in the fabrication of an afterlife that is hell does this actually mean, and more importantly, how does this actually work? Like, particles are just field excitations right? What the heck is exciting them? Where are these fields even located anyway? Are they these physical/metaphysical regions of space that we can travel to? Did these fields always exist, or were they put together by someone/something? Are there fields for antiparticles as well as regular particles? Is there one Electron field for every single Electron in the entire universe, or is every single Electron in the universe a part of a single field? How does particle decay tie into all of this? Does Dark Matter get its own field as well? What about Atoms and Molecules? Where do they fit in all of this? Seriously, I cannot stress how much this single statement destroyed everything I thought I previously knew about matter and the sub-atomic world.       

[Colin2B]

Ok so, around two-ish months ago, I was told by a Cosmologist that what we perceive as matter doesn't actually exist and that the alleged particles that we think it's comprised of are actually "Excitations of fields intrinsic to the universe."

We did reply to this in your other thread. What he is saying is misleading.
Unfortunatly unless you are prepared to put some serious time into understanding what a field is, you are likely to end up very confused.
Did you know there is a field theory of knots?

Fields are descriptions of what we observe. For example, we could describe the temperature in a room as a 3D field (a scalar field)with a specific temperature at each point. We might see a 'hot spot' on one side of the room and could call it a radiator or an excitation of the temperature field. In a similar way a tornado is an excitation of the wind field (a vector field having magnitude and direction).
The benefit of describing things by means of fields is that there are some very useful maths for handling vectors that allow us to describe and predict the behaviour of particles described in this way.

To be honest this really shouldn't shake anything in your perceptions. If you know anything about physics it is that there are many ways of describing the physical world, mass, charge, as wave behaviour, atoms, molecules etc. Field description just adds to the toolkit.

[Aeris (OP)]

We did reply to this in your other thread. What he is saying is misleading.
Unfortunatly unless you are prepared to put some serious time into understanding what a field is, you are likely to end up very confused.
Did you know there is a field theory of knots?

Fields are descriptions of what we observe. For example, we could describe the temperature in a room as a 3D field (a scalar field)with a specific temperature at each point. We might see a 'hot spot' on one side of the room and could call it a radiator or an excitation of the temperature field. In a similar way a tornado is an excitation of the wind field (a vector field having magnitude and direction).
The benefit of describing things by means of fields is that there are some very useful maths for handling vectors that allow us to describe and predict the behaviour of particles described in this way.

To be honest this really shouldn't shake anything in your perceptions. If you know anything about physics it is that there are many ways of describing the physical world, mass, charge, as wave behaviour, atoms, molecules etc. Field description just adds to the toolkit.

Soooo... fields, as I've described them in my question don't actually exist and are just an easy way to describe how something in the physical world works and behaves?

[Halc]

Ok so, around two-ish months ago, I was told by a Cosmologist that what we perceive as matter doesn't actually exist and that the alleged particles that we think it's comprised of are actually "Excitations of fields intrinsic to the universe."

It means that fundamentally, matter isn't the stuff with classic properties that we might find intuitive.
Note that matter is made of 'excitations', not made of 'fields' which the title suggests.

Where are these fields even located anyway?

Colin2B gives a good reply to this reference to fields as existing objects, which doesn't work.

Did these fields always exist

A field doesn't seem meaningful outside the context of what is our spacetime. As to 'always', um... there is not a time in which say one could not meaningfully express a measurement of a particular field. This is debatable. Just after the big bang (well under one second), the 'fundamental forces' had not yet separated into those that we know today, and thus their fields may not have been meaningfully distinct at the time.

Are there fields for antiparticles as well as regular particles?

I'm not sure of this. I had understood that a particle and its antiparticle are different excitations of the same field, but it could also be that they're separate fields with symmetric properties.

Does Dark Matter get its own field as well?

Jury out. There's no viable theory of the nature of dark matter at this point. It seems to affect spacetime, which involves gravitations fields, but it seems to not involve other known fields nor even new ones since except gravitationally, it seems not to interact with itself in any way.

What about Atoms and Molecules? Where do they fit in all of this?

Same as people. They're complex things composed of simpler things. They ride the line of classic physics.

Seriously, I cannot stress how much this single statement destroyed everything I thought I previously knew about matter and the sub-atomic world.

Why? What did you 'know' before? The nice classic model of atoms made of nice colored balls with orbiting electrons? That went out the window quite some time ago.
Even the model above (excitations in fields) is more classic than is suspected. It suggests that the field is always in some objective state, however much known or not. This is probably not the case, but some suggest that it is, preferring to abandon rules like cause preceding effect, which I personally find distasteful.

Soooo... fields, as I've described them in my question don't actually exist and are just an easy way to describe how something in the physical world works and behaves?

We measure their values, so that's existence in my book. I suppose it depends on your definition of 'exists'. A field usually cannot be measured directly. Only excitations (differences in the fields at different events) can be meausred. For instance, I cannot measure the gravitational potential of Earth at sea level, but I can measure the change in that potential between sea level and 100 meters up.

[Colin2B]

Soooo... fields, as I've described them in my question don't actually exist and are just an easy way to describe how something in the physical world works and behaves?

They don’t exist in the way you think about them, but what they measure and model are real enough.
Temperature exists, wind exists, the effect of what we call a magnetic field exists.
The last one is a really good example. We define a magnetic field by the force and direction of that force (vector) on a test magnet at a particular point. The force on the magnet is very real, it’s effect is one we can feel. The field is how we describe it.
This field does exist in all space, because in theory the field from one fridge magnet goes out to infinity, although it would be so small as to be impossible to measure it even at a few meters. So now you need to ask a question, does the field cause the magnet or does the magnet cause the field. Field theory doesn’t care, it just describes and predicts the behaviour of things affected by the magnetic field - there you see, our limited language forces us to attribute action to the field 
Not everything is cut and dried, as @Halc says current view is that particle & antiparticle are described by the same field, but we might find something in the future that changes that.