Key Difference: Facts are something that has actually occurred or happened. Facts can be verified or proven using standard references or scientific experiments. Opinions are subjective beliefs of either one person a group of people and these need not be true. Opinions are the result of emotion or interpretation of facts.
Facts and opinions are two words that we come across very commonly. These terms are used in our daily lives when we say something. Facts are things that are based on the truth, while opinions are what a person believes, which may or may not be a fact.
The term ‘fact’ is derived from the Latin word ‘factum’ meaning "a thing done or performed", but this definition is now obsolete. The new definition of fact states something that has actually occurred or happened. Facts can be verified or proven using standard references or scientific experiments. The word fact is sometimes used synonymously with truth. Scientific facts usually arise from scientific inferences, an educated guess or opinion, made by a person, though it is not a fact until is proven. Facts are hard core and hence they cannot keep constantly changing; a fact remains a fact until proven otherwise. For example, people used to believe that the world was flat, until observational evidence proved it to be a sphere. Ferdinand Magellan is credited with proving the world is not flat when he and his crew were the first to complete the circumnavigation of Earth. Facts are also universal and they do not change according to region, cast, culture, religion, etc. Laws such as Law of Gravity, Boyle’s Law, etc are also considered as facts.
Opinions are subjective beliefs of either one person a group of people and these need not be true. Opinions are the result of emotion or interpretation of facts. An opinion can be supported by an argument, which can create two opposing opinions from the same set of facts. Opinions can be a result of a person's perspective, understanding, particular feelings, beliefs, and desires. These are various types of opinions: Public/consumer opinion, scientific opinion, legal opinion, judicial opinion and editorial opinion. Public or consumer opinion is an important part of marketing and advertising, which takes the opinion of a group of people in order to see if a product will be successful in the market or no and if so, which type of audiences will it be most popular with. Opinions can vary and are not set in stone; they can also change from persuasion or circumstances. Opinions can also become facts, when proven and it is believed that almost all facts were opinions before they were proven. An opinion can be influenced by culture, religion, society, etc. Gossip and editorial columns are types of opinions.
Facts and opinions are a part of our daily lives and we come across it every day. While, some people claim that their ideas a facts, this can or cannot be true. Only if the opinion is proven by some experiment or proof then it can become a fact, otherwise it is just an opinion.