Critical thinking requires the ability to analyse statements into facts, assumptions and interpretations. Facts can be checked, assumptions can be challenged and interpretations argued. That's intelligent debate. Most people will come at you with interpretations and facts, but to fully understand their position, you need to know the assumptions that have supported their interpretations. Anyone who says they aren't making assumptions either doesn't know what their assumptions are, or they aren't making logical arguments.
Mokalus of Borg
PS - You can't make logical arguments without assumptions.
PPS - You could try, I suppose, but they would fall over on their own.