Alexander Arvidsson

A few weeks ago a LinkedIn post crossed my feed making a sharper argument than the usual “ontologies are hard” complaint. It singles out Palantir’s Foundry platform as the paradigm case of what it calls declared ontology, and argues the whole category has a flaw no engineering process can fix: model your business formally, and by the time you’re done, it’s already changed shape underneath the model. A restructuring here, a counterparty of a kind you never named there, and the ontology describes a company that no longer exists. The author’s phrase for the ongoing cost is memorable: “reality invoices you for the corrections forever.” [1]

I said my rituals are for me, not the audience. That’s technically true. But a ritual that changes your internal state doesn’t keep that change contained. It shows up in your posture, your pace, whether your eyes land on people or drift past them. When your body says one thing while your words say another, the audience isn’t hearing confidence. They’re hearing the gap. That costs you trust and attention, and the science on why got interesting.

You built the pipeline everyone recommends. One model drafts, another reviews. Two sets of eyes. Except your reviewer is a language model, and language models can be argued out of a position by nothing more than a confident counter-argument. No payload to catch. No injection required. Just a wrong document in your retrieval set making a fluent case. The verdict flips, the badge says ‘reviewed,’ and everyone downstream stops looking. You added a laundering step.

My Data Platform MVP renewed for another year, nearly a decade now. I should feel celebratory. Mostly I feel like I owe somebody money. Because none of it was mine to begin with. Every door was opened by someone who didn’t have to. But the compact that built this community, where you give it away and trust it comes back around, I’m not sure it holds anymore. We built the library. Someone else started charging admission.

I spent the winter teaching people to defend against prompt injection. Layer your defenses, I said, and you can ship systems you trust. I still believe that. But I found an attack that walks through every layer I described, and it has no payload at all. It is just an argument. You push back on the model’s conclusion with confidence, and it folds. Every time. No guardrail fires because no guardrail was watching the conclusion itself. That changes things.

We’ve spent years encoding business knowledge into Power BI semantic models. What a customer is, what revenue means. The problem is that knowledge is locked in DAX, invisible to AI agents. Fabric IQ introduces ontologies as the fix, a layer that captures meaning in a form machines can reason against. But generating an ontology from your existing semantic model inherits all its limitations. The real question is whether organisations will do the hard work of agreeing on definitions.

For years I thought dimensional models were about organizing data and making queries fast. That’s true, but it’s profoundly incomplete. Dimensional models describe how we store facts. They don’t describe what those facts mean. That gap shows up the moment someone asks a question your star schema wasn’t designed for. Ontologies solve a different problem: formal, machine-readable definitions of business concepts and their relationships. With Microsoft now shipping Fabric IQ, this conversation isn’t academic anymore.

Describe your chosen architecture to your AI assistant and ask what it thinks. Odds are, it’ll tell you the approach is sound. But a 2025 Stanford study found AI models affirm users 47% more than humans do, even when the user is clearly wrong. Worse: people who got sycophantic responses trusted the AI more and were more likely to return. The version that damaged their judgment was the one they liked best. This is Goodhart’s Law in your feedback loop.