The former deputy chief inspector of schools is carrying out a government review of the primary curriculum, which heads have long complained is overcrowded.
He told the Westminster Education Forum that some saw primaries simply as "all about caring and sharing before the real education started in big school". It was crucial that the primary curriculum was not simply seen as a bridge between early years and secondary, he said.
"We've a great many schools that are very good - schools that deserve to be recognised," he said. "Ofsted has found many world-class exemplars. It's not all gloom and doom, and my review has to be careful not to destabilise the good."
Sir Jim's final report is due in March 2009 and will be followed by consultation, then any changes will be implemented in 2011.
He hinted that his recommendations were likely to include retaining subjects rather than regrouping the curriculum into wider themes.
"In terms of responses so far, there is an appreciation that the subject disciplines have a proper and rightful place," he said.
Sir Jim was one of the "three wise men" - with Robin Alexander and Chris Woodhead - who in 1992 wrote Curriculum Organisation and Classroom Practice in Primary Schools, which condemned topic teaching. This prompted a shift towards subject teaching, which has recently reversed as primaries struggle to cover a packed curriculum.
Kevin Jeffery, who trains teachers in themed curriculum work, said: "I'd be worried if we were told we shouldn't have themed teaching, but also if they said we should. What I want is for people to say, 'If you're going to do it, do it well.'"