All expressions of form are conditioned, and conditions can only be probed by formless awareness, which is still and not conditioned. If we attempt to investigate conditionality with other conditional processes, such as our thoughts or opinions, we will be unable to see through the filters of our thoughts to what is actually there. Stillness, being unconditioned, is the only avenue for penetrating into the nature of reality.
Note: How to investigate with stillness/awareness?