What technique is most crucial in identifying the underlying assumptions when critically analyzing an argument?

The technique most crucial in identifying the underlying assumptions when critically analyzing an argument is explicitly questioning the stated premises and exploring alternative viewpoints. Underlying assumptions are unstated beliefs or principles that support the argument but are not explicitly articulated. To uncover these assumptions, one must actively probe the stated premises by asking 'What must be true for this premise to be accepted?' and 'Are there other possible explanations or interpretations?'. Furthermore, exploring alternative viewpoints, and considering how others might see the issue, can expose assumptions that the original argument takes for granted. This process involves active skepticism and a willingness to challenge the surface-level logic of the argument to reveal the deeper, often unacknowledged, beliefs that underpin it.