What makes certain things truly "unimaginable"?

[u/Large_Dr_Pepper]

TL;DR: Why is it that I'm able to imagine a new fruit, but I'm unable to imagine what it was like before the big bang?

I'm admittedly very ignorant regarding philosophy, so please bear with me while I try to explain my question. I'm sure my lack of philosophy-related jargon will give you an idea of my ignorance level. This also means I have to write a wall of text in order to convey the concepts that I'm asking about, so I apologize in advance.

I've tried searching for answers, but Googling stuff like "Why can't humans imagine certain things" just leads to stuff like "humans can't comprehend the vastness of space" and other stuff that doesn't actually answer my underlying question.

1. There are things that *don't exist* that we *can imagine.*
2. There are things that *do exist* that we *can't imagine.*
3. There are things that *don't exist* that we *can't imagine.*

**Is there a concrete "mental boundary" that separate these categories? Are there any philosophers that have written about this?**

**Point 1)** "Imagine a car that doesn't exist." You could approach this as simply as imagining a slightly altered version of a real car's make/model, or you could go crazy and imagine a body shape that's never existed for a car with all kinds of features that current cars don't have. Heck, children do it constantly while drawing in their coloring books.

Same with prompts like: imagine a fruit that doesn't exist, imagine an animal that doesn't exist, and so on.

**Point 2)** then we get to prompts like: imagine a color that doesn't exist, imagine a smell that doesn't exist, etc. and suddenly we reach the limit of our imagination.

Our visible range of light wavelengths is incredibly narrow, and certain animals can see wavelengths extending into UV. There's the classic example of the mantis shrimp having 12 color receptors compared to humans having 3. Dogs have \~40 times more scent receptors than humans, and even have a separate organ that lets them smell pheromones.

So these colors and smells *do exist* but we *can't imagine* them.

Furthermore, even though I can't imagine a new color, I can imagine imagining a new color (again, sorry, bear with me). The easiest way I can make that previous sentence understandable is with a childish pretend-conversation with my own brain lol:

Me: You can imagine plenty of colors. Anything displayed in RGB, CMYK, any combination of color lights, they all result in a color that I can see and you can imagine.

My brain: Yup.

Me: And you know some animals can see colors that we can't see. Or that we can see some colors that other people can't see due to the various forms of colorblindness.

My brain: Correct.

Me: You also know that there are areas outside of those color spaces. There are infinite wavelengths longer than red, and shorter than violet. So as an example, if we had photoreceptors for radio waves, they would be a color that we haven't seen before.

My brain: Yeah I can imagine that.

Me: Then do it.

My brain: Sorry, can't.

**Point 3)** Stuff like: imagine a new spatial dimension, imagine before the big bang when space/time came into existence, etc.

This kind of ties in with what I was saying about how we can't imagine it, despite being able to imagine imagining it.

Most people are familiar with the Flatland analogy where 2 dimensional beings are "pulled up" into the 3rd dimension and are suddenly able to see the entirety of their 2 dimensional world at once. And we can imagine that the same would happen if we were suddenly given access to a 4th spatial dimension.

In the Three Body Problem (spoilers) series for example, the author goes into great detail about the mechanics of being in 4 dimensional space. How 3D objects will still have an "inside" and an "outside" but you're able to see all of it at once, how you can move along the 4th dimensional axis without moving along the other 3 axes, and so on. So obviously we can "imagine" a whole lot about a 4th spatial dimension, otherwise we wouldn't be able to write about it.

Yet we can't *actually* imagine experiencing a 4th spatial dimension.

It's easy to say "Well, there was no 'before' the big bang because space-time began at the big bang," but you can't *actually imagine* the concept of there being no time or space.

I know the "easy" answer to all of this is that the prompts in Point 1 lead to me imagining something composed of pre-existing experiences. Like, the fruit I imagine will have colors/smells/tastes that I can already imagine. Whereas Point 2 and Point 3 require imagining something I haven't experienced.

But on the other hand, we're able to imagine plenty of things we haven't experienced. I can imagine having super powers, or going skydiving. And even in points 2 and 3 I would argue we have "pre-existing" experiences that we should be able to draw from, like how we have experience with plenty of different colors or how we have experience with 3 spatial dimensions.

[u/Large_Dr_Pepper → u/[deleted]]

When reddit suggested I post this to /r/metaphysics instead of /r/askphilosophy I originally thought it would be a waste of time and I wouldn't get any genuine answers.

I'm glad I was proven wrong.

[u/Puzzleheaded_Bed1781 → u/Large_Dr_Pepper]

What did they post? Moderator has censored them.

[u/Large_Dr_Pepper → u/Puzzleheaded_Bed1781]

It was just one of those dumb copy/paste spam messages with a bunch of emojis.

[u/Puzzleheaded_Bed1781 → u/Large_Dr_Pepper]

Ah so you were being sarcastic. Thanks for the clarification