What a lens does
By default, every analysis convenes the full table: every discipline, weighted by its relevance to your question. A domain lens adjusts that emphasis. It asks the analysis to lead with one field's evidence and vocabulary while still drawing on all the others. The key idea is that a lens shapes emphasis, not exclusion: it changes the order and the framing, never what gets considered.
Why the General lens is the default
General is the platform default. It gives the full multi-disciplinary treatment and lets the analysis work out which fields matter most for your specific question, then organizes around that. For most questions this is exactly what you want: every perspective on the table, without deciding in advance which frame should lead.
If you are not sure which lens to pick, General is almost always the right answer. Reach for a specific lens only when you have a clear reason to.
When a specific lens helps
Choose a specific lens when you already know the angle you care about most and you want that field's evidence and framing to lead. A clinician researching a treatment question might choose the Medical/Health lens; a founder weighing a market move might choose Business; a teacher preparing a lesson might choose Educational, which is tuned for learners with clearer explanations and more context.
The lens never removes the other disciplines. A scientist using the Scientific lens still sees the philosophical arguments and the historical precedents; a philosopher using the Philosophical lens still sees the empirical data. The analysis is simply organized to speak the language of the field you chose.
Choosing a lens is low-stakes
Picking a lens is not a decision you can get badly wrong. Because every lens still shows you every perspective, the worst case of an off choice is emphasis you did not need, not a missing argument. If a lens does not fit, run the question again under General or a different lens. The analysis is quick to redo, and your question does not change.
The lenses at a glance
There are eighteen domain lenses, grouped into five families (Humanities & Philosophy; Law, Policy & Governance; Sciences & Technology; Applied; and Arts & Expression), plus the General default. Each one has a short description of what it emphasizes.