Why Is More Important Than How
In software architecture, the rationale behind a design decision—the “why”—is fundamentally more important than the implementation details that follow—the “how.” This principle shifts focus from technical execution toward the architectural reasoning that justifies decisions.
The Core Principle
When architects make decisions, they communicate two distinct pieces of information: what they’ve decided and why they’ve made that choice. While the “what” describes the technical solution (microservices architecture, event-driven patterns, layered structure), the “why” explains the business context, constraints, and trade-offs that motivated the decision.
The “why” remains constant across organizational transitions, technology evolutions, and team changes. The “how”—the specific implementation—evolves continuously as technologies improve, team capabilities grow, and organizational needs shift.
Why This Matters
Understanding the architectural reasoning enables better decision-making at every level:
For future architects: When the original decision-makers leave, their reasoning remains documented and discoverable. New architects can evaluate whether the original constraints still apply and whether different trade-offs might now be preferable.
For implementation teams: Knowing why a pattern was chosen helps teams implement it more effectively. They understand the boundaries within which they can optimize and innovate. They avoid accidentally undermining core architectural intent while pursuing local performance improvements.
For stakeholders: The “why” connects technical decisions to business outcomes—cost efficiency, time-to-market, risk mitigation, scalability requirements. This alignment is what makes architectural decisions defensible and maintains stakeholder trust.
For evolution: When circumstances change—perhaps a new business requirement emerges or technology landscapes shift—understanding the original “why” allows architects to evaluate whether the current “how” still serves its purpose or whether a new approach might better address the underlying concerns.
Documentation as Architectural Tool
The architectural decision record (ADR) formalized this principle: capturing not just what was decided and when, but crucially, why. The alternatives considered and trade-offs accepted become the permanent context that justifies the current state.
This transforms architecture documentation from static artifact into living knowledge that guides evolution and prevents architectural drift.
Related Concepts
- Architectural Decision Records - The practical tool for documenting architectural reasoning
- Quality Attributes - The business and technical drivers behind “why” decisions matter
- Trade-offs in Architecture - Understanding competing concerns that justify specific choices
- Conway’s Law - How organizational structure (another “why”) influences architectural choices
- Evolutionary Architecture - How understanding “why” enables thoughtful architectural evolution
Resources:
Note
This content was drafted with assistance from AI tools for research, organization, and initial content generation. All final content has been reviewed, fact-checked, and edited by the author to ensure accuracy and alignment with the author’s intentions and perspective.