Unconscious assumptions define the aperture of thinkable thoughts
Every idea comes packaged in an implicit frame. Philosophers know this, so they tend to critique the premise — the frame — rather than the conclusion. When searching for answers, most people are like the proverbial drunk who only looks for their keys where the light is shining. The spotlight distorts thinking and limits the ideas you can discover. Good philosophers spend as much time studying the spotlight as the ground itself.
Chomsky's version: the modern limits on speech are implicit, not explicit. By law you can say almost anything. But in practice there's a frame around acceptable opinions that allows lively debate only within that range. The assumptions of a culture determine the aperture of mainstream thinking. That's how thought control happens without explicit prohibition.
It took two years of research and conversation with orthodox Christians to surface the unconscious assumption that belief in human rights has nothing to do with religion — and to see that the assumption was wrong. Like a teenager who wears what everyone else wears, we unconsciously accept the intellectual assumptions of our social environment. Only by spending time with people you mostly disagree with do you see the myopia of your own worldview.
When you restrict yourself to one side of the intellectual spectrum, you limit your capacity to find truth. The frame itself is invisible until you step outside it — and you can't jump to conclusions outside the spotlight.
Source claim: The unconscious assumptions of your cultural environment define what thoughts are thinkable — and philosophers make their mark by attacking the frame, not the conclusion.