"We Cannot Do This" Means Three Different Things

A developer says "we cannot do this."
A director says "this is required."
An architect says "this is permitted."

Each statement sounds like a fact about the work. Each is actually a statement about the kind of constraint in play. And each kind requires an entirely different response.

When a developer says "we cannot do this" and means it is technically impossible, no governance decision changes that. The constraint is alethic: it holds because of physical law, logical necessity, or the nature of the system itself. Reaching for authority is the wrong tool.

When a developer says "we cannot do this" and means it violates a regulation, the constraint is deontic: it holds because an institution established a rule. That rule can be changed, waived, or interpreted differently. Authority is precisely the right tool.

Conflating these two produces debates that cannot be resolved. Adding information does not help. Adding governance does not help. The conversation has no resolution because the parties are applying different kinds of constraints without realising it.

The same applies to obligation. What is normatively obligatory, mandated by policy, is not physically necessary. The obligation can be revised. The physical constraint cannot. Treating them as the same kind of thing is how organisations spend months defending positions that were never actually in conflict.

This is not a rare edge case. It is embedded in the everyday language of architecture and governance. "Required," "recommended," and "optional" are used interchangeably in most governance documents. They are not interchangeable. Required can mean obligatory, or it can mean necessary. Optional can mean permitted, or it can mean non-necessary. Each combination carries different implications for who has the authority to change it and by what means.

Modalities — alethic and deontic — provide the vocabulary to make these distinctions precise. They do not reduce the complexity of architectural work. They make that complexity negotiable.

The full vocabulary is developed in the full article: Beyond Blueprints: The Constraints on Strategy, Design, Architecture, and Interweave.