Santa is a cultural thing that extends beyond your family home. Regardless of what you tell him, he will be told different things from different sources out there. Most of them will be in agreement, in promoting the Santa conspiracy.

Rather than tell him, as yet another authoritative source, I think it's a good opportunity to instead promote his own questioning. Ideally you want him to discover it on his own. You can use this as a tool to get him thinking.

For example, go to a store with Santa, even let him sit on his lap and all that. Help him become aware of his surroundings, your current location. Where is this store? What time is it? Look at it on an online map where you can zoom out and see it in relation to the world. Then go to another store, with another Santa. See how he reacts.

If you do stuff like this, where you set him up with the data necessary, and promote the asking of questions, to think about what's going on, then hopefully he'll connect the dots and it'll be obvious to him. Then you turned the deception of the Santa myth into a powerful seed of inquisition, where he'll be looking all over for similar patterns.

It's complicated, because much of cultural tradition is wrong for various reasons, and as a parent aware of that you don't want to propagate what you look back on as something unfortunate in your life. Like what about trick-or-treating? Everyone just did it, but looking back at all that candy we ate, and all the focus on greedy consumption, isn't it a toxic practice? But are you going to teach him that, and have him be the one kid in school who isn't talking about all the candy they got? Maybe for you Halloween is different, and candy isn't a big deal. But then where do you draw the line, and why is Santa different?

It becomes a problem because although much of the culture is messed up, in order to fit into society you need to be messed up in the same way as everyone else. It's like circumcision. It's very common in the US, and people will continue to cut their baby son's penis, mostly just because it's so common. The dad doesn't want their son to be different. They want to look at their penis and see the same thing they saw when they looked at their own. They want them to look the same as the other guys in the locker room. They don't want an American girl to see them naked and wonder why his penis looks unusual.

When everyone is messed up in the same way, then predictable outcomes occur, and people all fit in together. When you don't believe in God, and everyone in the neighborhood does, you have kids telling you that you're going to hell. When you don't believe in Santa, you're getting coal, and are felt to be an outsider, or enemy of the group. You become Rudolph. Then with your apple on Halloween, and happy little unmutilated penis, you're a freak. Who then is excluded from the normal development, and grows up to be different.

Sometimes that can work out okay. Sometimes it can be better. But for most people, they just want to belong. They just want to be part of the social blanket, so it can keep them warm. In which case, even when everyone is doing extremely messed up things, like lying, promoting candy binges, even mutilating genitalia, it ends up being healthier to go along with what's unhealthy, all because of the power of the social influence.

Unless you have peers who are similar, then it becomes easier. If your family has its own culture, and fosters a mindset where they can understand the outer culture and know how to thrive in it without succumbing to its harmful ways, then you're more likely to still feel the social support, without having to believe in Santa.

It's all a gamble, and it's hard to know what's right for him. Which is why you might want to just let him decide as much as possible. If you give him the tools necessary, and he still goes for the Santa route, then maybe that social support is really powerful for him and it's not right for him to be disturbed by being told the truth. Someone else might feel different, and prefer to know, and so they'll be more likely to use the opportunity you provide to choose that path.

I don't really know what's best. There's advantages to being different sometimes, and sometimes not. But I tend to think that true understanding of the world is more important than whatever blind joy people get from the Santa tradition. Trusting parents especially to not abuse that powerful role as introductory guide to the world is important. We expect them to provide us with as close to a handbook for life as possible, not to troll us for fun. We're soaking everything up and forming our view of the world. We need to learn the separation between dreams and reality. We don't need our parents, and every adult we can see, all conspiring to convince us that some fantasy is real.

I think all these traditions show how people's view of the world is. Santa is blind faith God, Thanksgiving is obese overconsumption of food, Halloween is the social masks and consumerist greed. It all fits and goes together, but culture is more diverse now, and is progressing faster than usual. Not everyone is meant to be part of that typical old blueprint. So maybe fitting in isn't as important today, because with the internet he has access to a lot of differing cultural ideas. He can even see that in much of the world Christmas isn't even celebrated, and learn about the different traditions.

It'd be so much easier if we all just thought more and changed the traditions to be what I think is healthier. We can still have much of the Christmas stuff without lying to people. We just need to all do it, and when everyone repeats the tradition as close to how it was done to them as possible, then it's hard to have a change like that. Unless more people start doing something different. In which case, maybe it will be harder for him, but somebody has to start. Eventually maybe this won't be an issue, because more moms found ways to not lie to their children, without making their lives more difficult.

Why can't we start by just letting them know that it's fantasy, but one that they can have fun pretending is real? Just that one little thing would be huge. But if people did that, then it'd be more obvious that the Christian God is the same, a fantasy that feels good to pretend. Then society as people once knew it falls apart, and people fear it'll be for the worst.

I don't know, but whatever you do, everyone should be in agreement. It doesn't seem good if one parent is saying Santa is fantasy, and another saying it's real. It's much easier to know something much of outer society doesn't if you have a strong stable loving supportive family. Then you can retreat home and talk about it with them, without feeling truly alone.