Assumptions are necessary when considering all but the most abstract ideas. Some assumptions are well supported and do not weaken the critical thinking process. Ensuring that all parties understand all assumptions helps when debating and discussing ideas.
Critical thinking requires using logic, but logic is dependent upon accepting premises. These premises are often called assumptions. Some premises are ironclad, such as assuming that an object dropped on Earth will fall and land safe. Others are unknown. Ensuring that assumptions are correct is essential for creating a well-formed argument.
However, correct assumptions are not always necessary to the critical thinking process. Debating future events requires dealing with assumptions that may not be true. Particle physicists must deal with unknown assumptions when considering advanced concepts. Critical thinking can deal with abstract concepts, but the conclusions drawn might not reflect reality.
While debating and discussing ideas, people sometimes operate from differing assumptions, and these can cause debates to stagnate. If one person believes that the planet is warming and the other debater does not, discussions about governmental responsibility are unlikely to yield useful results. Before engaging in debate, all parties should reveal their positions on various assumptions. If they cannot agree, debating the assumptions might be worthwhile.