Not if you don't care that it will be much less of a system. Even the PS3 was designed to play online. Most but not all PS3 games are singler player when not online.
can you play destiny on the ps3 and play with a friend that has destiny for the ps4
The PS3 will not be able to play the PS4. They both are on the Playstation Network (PSN) and Playstation Plus will work for both of them as it does for the PS Vita and PS3
No you will not be able to play the games either way. Systems changes on the PS4 allow them more design capability for games and many titles will be released in a downgraded PS3 version. You still will have to have a PS4 to play PS4 games and a PS3 to play PS3 games.
You will be able to play it on both the PS3 and PS4 gaming consoles. The beauty of Playstation is that you can access their games and titles via consoles, along with wireless and remote devices.
No, it is impossible to play with someone who has a different console to what you do, you also can't play xbox 360 - xbox one and ps3 - ps4.
No, the PS4 does not have backward capability and cannot activate (play) PS3 or PS2 games.
No it will not
No, the PS4 will only run the games made for the system. But there is a application on PS4 called PlayStation Now which will allow you to play PS3/PS2 games for a price.
Keep the PS3 and play with your friends and wait for them to get it, or you can just buy a PS4 and wait for them to get one.
In short, no. Sony haven't released any information regarding a PS4 yet, so we can only assume that you cannot. It is highly likely you will be able to play PS3 games on it, that is - if it really comes out.
No