I think this question must be subjective about whether they look alike or not... Because I think they totally look like brothers separated at birth. Seriously. I remember being excited about the announcement that Brothers was in the works because for ages I've been thinking that Jake and Tobey should be in a movie together as relatives. I don't think they look completely different at all. And, to me the big eyes is probably the key feature that casting folks were thinking about in terms of resemblance.
I would never mix them up, but yeah, I think there's a total likeness. And, it's totally shocking to me to think that Tobey is older. To me he looks a lot younger... especially when Jake has facial hair. When Jake is clean shaven, to me he looks years younger than he does with stubble or moustaches.
Me neither. They look completely different. And that's my problem.
Maybe I'm getting too detail-oriented, but I'm having problems with movies about brothers or sisters where the actors don't look anything like each other. Unless there is some excuse - they're really half-brothers and don't know it, or they're adopted and don't know it, or something similar, I have a hard time suspending disbelief. I had real problems with the movie Cassandra's Dream.