Written for the other thread before it was locked:
Music is created by the artist and offered for sale to the public. Illegally downloading music is not okay, because it means taking that music against their terms.
I'm not talking about someone who shares an MP3 with one friend, who then goes out and buys the album himself if he likes the song or deletes the file if he doesn't. That's a grey area, because it's somewhat like a virtual version of lending someone a CD. I'm talking about illegally downloading an album, with no intention to ever pay for it. That's wrong because it violates the artist's ability to decide what is done with their intellectual property.
I have to say I think "illegal downloading" is way overblown. These streaming music services pay artists jackshit and make a ton of money for themselves. I think that is more wrong than some teenager downloading a few songs that he probably wouldn't buy to begin with.
This, to me, demonstrates that you don't really understand the issue. The issue is not exactly how much money the artists make, the issue is that, when Dream Theater creates an album, it is their intellectual property and they are allowed to decide how it will be distributed to other people. So if they choose to make a deal for their album to be on Spotify, even if it's a bad deal for them, they still made that choice, which is what matters. They did not choose for the album to be simply taken by thousands of people who did not pay for it.
I agree that streaming services have some issues regarding how much they pay artists. And, fortunately, artists like Taylor Swift are being very confrontational about how this works, trying to make things better not just for big artists, but for small ones who are just getting started. But it's not worse than illegal downloading. Using Spotify is not immoral, because the artists consent for their intellectual property to be on Spotify. They do not consent to people stealing their albums.
I also think the comparison of groceries and music is ridiculous. When someone plays a song in a room (or in a grocery store), everyone gets to hear that. When someone eats a sandwich, only the person that is eating gets to enjoy it. Intellectual property does not equal food. If someone steals a loaf of bread and eats it, that bread is gone forever. If someone steals a song and shares it, it is still available to listen to and be purchased.
Whether you agree or disagree (and I admit this is not a clear cut issue), those are two very different and incomparable things.
It's true that scarcity is an aspect that is different between physical property and intellectual property. But as I said, the key issue is the artist's ability to control their intellectual property.
Imagine this scenario. Imagine you wrote a book. Put eBooks aside for a moment because that's an unnecessarily complicating factor. Now, imagine that one person bought your book, scanned all the pages, then posted it online. And no one else bought the book, instead reading the online post. Does that not seem like theft? Instead of paying for your intellectual property, the way you wanted them to, they chose to steal it. Your Spotify example might be the equivalent of an author choosing to host the complete text of his book on a website that charged readers a monthly fee and paid the authors 5 cents per reader. That's not a good deal for the author, and it's worthy of discussion, but because the author chose to use that website, it's not wrong like piracy.