This is certainly a judgement call for each parent to make...
As I see it, I love the concept of Santa, and even though I know the man in the red suit with the sleigh and 8 reindeer isn't true, there was St. Nicholas who helped the idea begin....there are some truths that the fiction is based on.
But that's not what my real point is.
Even though I know "Santa" isn't real, I would still say "I believe" if asked...especially by children.
Several years ago I was working with a group of 4th graders and found a group discussing whether Santa existed or not...some still believed, others had "outgrown" the concept. I told them I still believe in Santa, and told them stories from when I was a girl--things Santa wrote in his reply letters after eating the cookies and feeding his reindeer the vegetables...Even those who no longer believed took delight in the tales.
And still I am not getting to my real point. LOL
I would say that belief in Santa is similar to a child having an imaginary friend. Not only do they both foster a child's imagination, it is something that is "needed" at that point in time. I certainly wouldn't tell a child that his (universal term in my book) imaginary friend doesn't exist...
I am delighting in carrying on the tradition of letters to and from Santa with my son as my Dad did with my sister and me. If it helps foster a child's imagination, then I believe. It could be difficult for a child who does believe to hear a friend insist Santa doesn't exist...
But as I said, it is a judgement call each parent needs to make.
Cheers everyone.
Mary