When we look at the sky, there is a line where there is way more stars than usual. This line goes all the way around the sky. This was called the milky way by the Greeks because it was like a road sparkled with milk drops. At some point, we deduced that we were in a group of stars arranged in a flat disk. Later, we realized that some weird space clouds (nebulae) were much further away than we thought and were actually other huge groups of stars like our own that we named galaxies, still after milk.

There are more details me course. Even along the line in the sky drawn by the milky way, there is one side where there is much more stars and dust than the other. We deduced that we were at the edge of the disk and the bright region was the center of our galaxy. Also, the amount of gas and dust that block certain types of light that teach us that our galaxy has arms.

How can you see your house if you are inside of it?

Wow. Amazing. Like what kind of an answer is "if you're inside a car you can see the car". This doesn't answer a damned thing!

We don't "know" what kind of galaxy we are in because we've never seen it from the outside. That would be impossible with our current technology.

Instead we have made very smart evidence-based assumptions as to how our galaxy looks.

What we know is that we are definitely in a galaxy because the general structure of the universe precludes such a conclusion. The extreme vast majority of matter is condensed in structures that are very uniform, we call them galaxies, therefore we must also be in one.

On a very clear night in certain parts of the world we are able to see in the sky a large elongated collection of stars which the ancients called the Milky Way because it resembles milk flowing down a smooth surface or something along those lines. What we currently believe is that that elongated formation of stars is an arm of one of the spirals that comprises our galaxy. We are also able to look at other structures using telescopes in our galaxy for example we have determined that we have a supermassive black hole in the center as many other spiral galaxies do as well.

So to answer your question we cannot see the Milky Way galaxy as a whole only certain parts of it and we've been able to draw conclusions by seeing other galaxies.

All the other comments here making neurotic epitaphs and idiotic analogies about how seeing something from the inside is the same as seeing something from the outside is just dumb and pompous if you don't know the answer don't say anything.

We're on the Earth — how do we see the Earth? By seeing other parts of the Earth that aren't ourselves. The same is somewhat true for the Milky Way. And like on Earth, you can't see the whole thing without leaving it, because we only get to see the stuff that isn't blocked by other things.

These analogy answers are weird and not helpful.

OP, they look through telescopes and figure out how far away the stars are. They record it in a little diagram on a computer and eventually they get a good idea of what it looks like from the outside.

In case you mean pictures like this; http://upload.wikimedia.org/wikipedia/commons/8/82/Milky_Way_Galaxy.jpg - they are not actually images of the Milky Way. As you've guessed, we can't directly see it in its full spirally goodness from the inside. Instead, these pictures are either artist's impressions based on scientific understanding, or pictures of different galaxies that are reckoned to be pretty similar to the Milky Way.

Because we are inside it. You can literally just look up at the sky and there it is! It does help that we are more toward the edge of it, than towards the center.

As for like a zoomed out image of the entire thing? Math as well as microwave and other radiation maps taken with powerful telescopes and instruments either on Earth or in orbit. Most of the images of space you might see are doctored in a way to make them look better to human eyes; they were actually constructed from data that wasn't necessarily visual. All the different colors of a rainbow nebula, for example, mean something, and the nebulas do not actually look that cool when seen with the naked eye.

The same way as I can see most of my body even though I am inside it. Indeed, without a mirror I cannot check whether I got a drunk tramp stamp tattoo last night, but I can still see most of my body and get a decent idea on the shape it as, especially when comparing with other's people bodies

The same way I see the hood of my car while sitting inside of it.

We do see it, just not all of it since the milky way is in the way.

If you're standing inside a cloud you can still see the cloud.

Same way you can see your living room

Epic Spaceman made a video about it where he showed how it looks from an outside perspective and our point of view while explaining a bunch of other things.

Imagine being on the surface of Saturn. You'd see the rings. I mean, you'd be dead, but you get my point I hope. If not, picture Saturn being the size of rock, but the rings were still there. You'd still see them, yet you'd be "in" Saturn.

Your question needs rewording because as its written right now the answer would be that you just look up at night and all the stars you see, are the milky way.

Picture you’re standing in a giant swimming pool. You can see the pool surrounding you.

Anyway it seems like that would be one of the best places to see the Milky Way.

It's very big, we're on the edge

Can you see the tip of your nose?