What a great question. Unlike most games out there, Eve does not require you to grind in order to level so in that case you could say yes. But the real 'meat' of the game is out in 0.0. Can you live for very long out in 0.0 just playing casually? Probably not so in that case you'd ahve to say no. But if you want to just do some missions or play the markets then in that case you could say yes. But if you have designs of space stations in your head that you want to build, in that case I'd asy no.

Either way, rathgryn in a fantastic post in the EveVault Forums answers the question quite eloquently...

"Eve can be played casually yet, in another way, it's impossible to enjoy at a casual level. Eve is a complex game, so the answer is complex."

http://evevault.ign.com/fullstory.php?id=28449