"We're still pushing for this year, but it would be sensible to focus on making sure next year's car is faster than this year's car."
The McLaren drivers have a similar record so far this season, each winning and retiring twice, but podiums in the last three races have lifted Button above Hamilton in the championship.
The 2008 champion has never been beaten by a team-mate over the course of a season but Button says the dynamic within the team will not change if he finishes the season higher than Hamilton.
"It will probably change more for you guys [the media] than anything in the team for us," he added.
"The points don't mean so much at the end of the year unless you win the championship, so I don't care about the points.
"I'm happy with the way I'm driving, with what the team are doing, with the way the car is, and that's the most important thing."
Commenting on the subject, Hamilton said: "Where I finish in the championship does matter to me, but it is the way it is. There's not much I can do about it at the moment."
Button and Whitmarsh reflect on Italian Grand Prix
A series of small mistakes have proved costly for McLaren. Hamilton lost the lead in Hungary when he made the wrong tyre choice and crashed out in Belgium as he tried to pass Kamui Kobayashi's Sauber.
Button retired because of hydraulics problems in Germany, saw his race end early in Britain when his right front wheel was not fitted correctly in the pits and had to battle to third from 13th on the grid in Spa after a "miscommunication" with his team in qualifying.
"We've had a couple of little mistakes, even in the last few races," added Button. "That hurts you when you're fighting against Red Bull and Sebastian because they are pretty flawless at the moment.
"Seb complained on Sunday about having a bad start - he lost one place! I went from third to sixth.
"So it's something we need to work on, to get everything together. You can't challenge them unless you do.
"Our pace is there, I feel good in the car, I feel confident. It's just getting everything together and then we can really fight for the wins."
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