Antonyms for the phrase "one can assume" could include "one cannot assume," "one should not assume," or "one must not assume." These antonyms suggest that assuming something without evidence or proof can lead to misunderstandings, errors, or false beliefs. Instead of assuming, one can use facts, data, or logical deductions to come to reasonable conclusions. Antonyms also encourage critical thinking, questioning assumptions, being open to alternative views, and seeking evidence-based arguments. By avoiding assumptions and using objective reasoning, individuals can make more accurate decisions, avoid biases, and maintain intellectual humility.