Sample Essay on PHI103 Informal Logic Week 1 Assignment

PHI103 Informal Logic Week 1 Assignment: Inference and Assumption

According to Paul (2007), critical thinking requires skills to think systematically and understand the elements of reasoning, which include purpose, information, inference, assumption, point of view, concepts, implications, and question. In this case, the focus is on the inference and assumption.

Inference is the process of obtaining idiomatic conclusions from a premise known or regarded to be true. The inferences can be precise or inexact, defensible or unjustified, coherent or illogical. The process may be valid but when applied to incorrect premises, it can result in either incorrect or correct conclusions On the other hand, assumption is what people take for granted or presuppose or something previously learned without questioning, therefore becoming one’s system of beliefs.

An assumption can be an answer that one arrives at by relying on personal knowledge of the external world; assumptions are never backed up by evidence from the text itself while inferences are (Sadana, 2012). Even if plainly correct, assumptions are constantly mistaken answer alternatives on standardized tests. Humans naturally believe and make assumptions, and derive inferences from them. Assumptions and inferences inculcate our lives since we cannot act without them, hence, they are applicable when making judgments, forming interpretations, and coming to conclusions based on the beliefs we have formed. Inference is a psychological procedure by which we arrive at a conclusion from precise evidence. Generally, the difference between assumption and inference is that when one infers, he/she makes more of an educated guess and that has more thought to it, but in assumption, one takes something for granted without really thinking about whether it is or is not true.

The one day I inferred was when my mother left my three-year-old brother in my care. She went to do some shopping but took much time than she anticipated, so the boy fell asleep upstairs in his bed. Unexpectedly, I heard a noise, “THUMP!” and he began crying hysterically, which got me worried. This made me run upstairs as fast as I could, inferring that he had fallen down. The assumption behind such inference is that most people assume that when they hear a sudden sound as if something has fallen down and the baby begins crying immediately, they think the sound is from a fallen baby.
One day when I was home, I heard some sounds of a siren outside the compound and quickly inferred that that there were sheriffs around. When I looked outside, I noticed that my brother was playing with his toy car. The assumption behind this inference is because only their vehicles are fitted with sirens.

Another inference moment was when I was in a supermarket. I saw a woman in soaked wet clothing and, since it was raining, I quickly inferred that she had no umbrella. When she left, I noticed she had an umbrella so I decided to ask how she got drenched. She said that as she was walking, she felt unconscious and fell down. The assumption behind this inference is that I believe that only those who do not have umbrellas get wet when it is raining.

The funniest of the inference moments was when I saw my mother wearing very black clothes. I thought she went to a funeral since it is an assumption that black clothes are only worn when attending funeral functions. When I decided to ask her, she said that the clothes helped her keep warm during the day because they both absorb and retain heat when it is cold.

The proper inferences were that of my brother falling down because chances were so high that he might have fallen down, and other was that of a siren since it is justifiable. An assumption in this case would not be valid considering the age of the boy. The remaining inferences were improper since conclusions were arrived at without further considerations, and they are not justifiable as wel


Paul, R. (2007, July 27). Critical Thinking in Every Domain of Knowledge and Belief. Retrieved from

Sadana, R. (2012, January 14). Inference Vs Assumption – GMAT Critical Reasoning. Retrieved from