Critical Thinking: Distinguishing Between Inferences and Assumptions
Introduction (Via Critical Thinking.org)
To be skilled in critical thinking is to be able to take one’s thinking apart systematically, to analyze each part, assess it for quality and then improve it. The first step in this process is understanding the parts of thinking, or elements of reasoning.
These elements are: purpose, question, information, inference, assumption, point of view, concepts, and implications. They are present in the mind whenever we reason. To take command of our thinking, we need to formulate both our purpose and the question at issue clearly. We need to use information in our thinking that is both relevant to the question we are dealing with, and accurate. We need to make logical inferences based on sound assumptions. We need to understand our own point of view and fully consider other relevant viewpoints. We need to use concepts justifiably and follow out the implications of decisions we are considering. (For an elaboration of the Elements of Reasoning, see a Miniature Guide to the Foundations of Analytic Thinking.)
In this article we focus on two of the elements of reasoning: inferences and assumptions. Learning to distinguish inferences from assumptions is an important intellectual skill. Many confuse the two elements. Let us begin with a review of the basic meanings:
Additional Excerpts (Via Critical Thinking.org)
1. Inference: An inference is a step of the mind, an intellectual act by which one concludes that something is true in light of something else’s being true, or seeming to be true. If you come at me with a knife in your hand, I probably would infer that you mean to do me harm. Inferences can be accurate or inaccurate, logical or illogical, justified or unjustified.
2. Assumption: An assumption is something we take for granted or presuppose. Usually it is something we previously learned and do not question. It is part of our system of beliefs. We assume our beliefs to be true and use them to interpret the world about us. If we believe that it is dangerous to walk late at night in big cities and we are staying in Chicago, we will infer that it is dangerous to go for a walk late at night. We take for granted our belief that it is dangerous to walk late at night in big cities. If our belief is a sound one, our assumption is sound. If our belief is not sound, our assumption is not sound. Beliefs, and hence assumptions, can be unjustified or justified, depending upon whether we do or do not have good reasons for them. Consider this example: “I heard a scratch at the door. I got up to let the cat in.” My inference was based on the assumption (my prior belief) that only the cat makes that noise, and that he makes it
Favorite bits (Via Critical Thinking.org)
We humans naturally and regularly use our beliefs as assumptions and make inferences based on those assumptions. We must do so to make sense of where we are, what we are about, and what is happening. Assumptions and inferences permeate our lives precisely because we cannot act without them. We make judgments, form interpretations, and come to conclusions based on the beliefs we have formed.
The point is that we all make many assumptions as we go about our daily life and we ought to be able to recognize and question them. As students develop these critical intuitions, they increasingly notice their inferences and those of others. They increasingly notice what they and others are taking for granted. They increasingly notice how their point of view shapes their experiences.