Realists consider scientific investigation to be a discovery, but anti-realists consider it to be a creation. For the realist, there is a "true way things are," and science is attempting to learn what it is; it seeks to discover the "truth." There is no possibility, according to the anti-realist, for objects to exist apart from how our ideas make them. Science is simply another way of creating knowledge about the world.
Realists believe that scientists use hypotheses to explain observations while anti-realists claim that scientists merely make observations and then try to fit their results into their existing framework. Anti-realists say that reality is not an issue for scientists because they are only interested in producing useful knowledge that helps them study nature more effectively. They argue that taking facts as true is unnecessary since they are always changing or could change at any time. Thus, anti-realists claim that truth has nothing to do with science.
Some philosophers have called themselves "post-modernists" or "post-structuralists" because they believe that modern philosophy is based on false assumptions about the nature of reality. While many post-modernists agree with classical realism that we can know things by studying them, they deny that reality exists independently of humans. Instead, they say that everything is a social construct - including theories and facts. Since facts are just collections of concepts without any independent existence, post-modernists conclude that there is no such thing as truth.
According to some philosophers, modern science was inspired by Plato's Academy.
Realists think that anything we believe currently is merely a rough approximation of reality, but that precision and completeness of understanding may be increased. In certain cases, realism is opposed to idealism. Today, it is frequently contrasted with anti-realism, as in philosophy of science.
The philosophical distinctions between pragmatism and realism are significant. Pragmatism regards scientific investigation as an endeavor to discover ideas that work, that make a difference, in solving a practical or intellectual issue. A realist believes in a mindless universe that scientific ideas seek to describe.
Pragmatism arose as a reaction against pure philosophy. The philosophers of ancient Greece were interested in seeking truth alone was not enough to lead to action or improvement in society. So they looked for ways to test the truth of statements such as "Socrates is a man" by examining how they could be used to predict certain outcomes - such as whether Socrates himself would agree that he was a man - and thus improve human life. Modern pragmatists continue this interest in practice and application.
Realism is also related to another point of view called instrumentalism. Instrumentalists believe that all knowledge is useful because it helps us solve problems or achieve goals. Thus, they argue, none of our beliefs are true by definition, since some may be helpful and others not. Pragmatists and instrumentalists both accept that we can never prove any statement to be true; we can only find out if it works. However, realists go further than pragmaticists and assert that some theories are better than others at predicting future events.
Finally, realism is closely linked with anti-rationalism.
Realists are those who argue the presence of genuine universals in and/or before specific objects, whereas conceptualists admit universals only, or mainly, as mental conceptions, and nominalists recognise only, or primarily, universal words. The term "realism" is often used instead to refer to any view that holds that there are real external objects independent from our minds.
The realism vs. nominalism debate was central to ancient Greek philosophy but it also arose within the Islamic world and in Medieval Europe. The debate arose because many philosophers were not satisfied with the account of universals given by Plato and Aristotle. They wanted to know more about what kind of thing a universal could be. Did universals exist independently of the mind? If not, then how can they possibly play a role in knowledge? And if they do exist independently of the mind, then why would we need to study them?
Plato and Aristotle agreed on one important point: Universals do not exist separately from objects that possess them. For example, when we say that all bachelors are unmarried men, we cannot mean something that exists apart from actual bachelors and unmarried men. We use the word "bachelor" to describe these individuals because it is to their advantage to be so classified.