Are the laws of science totally accurate? Can new evidence come up to negate what we have always accepted to be universal laws of nature? According to Karl Popper, no scientific theory is totally valid, because it is impossible to verify any one theory, although through experiments and observations, theories can be corroborated.

In his book The Logic of Scientific Discovery, Karl takes an insightful look at the methods of empirical science, trying to determine the validity of scientific theories, and to understand the point at which a hypothesis is considered totally proven.

Basically, Karl wants to make sure that scientific discoveries are made as scientifically and accurately as possible. He argues that it is impossible to prove a theory through experiments, because it is possible for one single experiment to contradict all the previous ones. Instead, he surmises that all scientific theories and laws must be based on falsifiability, that is, the possibility of them being nullified in future. A theory or law is considered falsifiable in cases where observations or arguments which would nullify the theory are even remotely conceivable. The more conceivable ways of a theory being nullified, the less likely it is to be valid.

A good illustration of Karl’s point is the discovery of the black swan. For ages, it was generally accepted that all swans are white, a generalization that was corroborated by numerous sightings of white swans. However, after the discovery of Australia and the subsequent sighting of a single black swan on the continent, the previous generalization was instantly nullified.

The Author

Karl Popper

The author of The Logic of Scientific Discovery, Sir Karl Popper was an Austrian-British professor and philosopher of science. He is reflected as being one of the greatest and influential philosophers in the 20th era. Apart from being a philosopher of science, Karl was also a self-professed critical-rationalist and a philosopher of sociology and politics who was lauded by many of the 20th century intellectuals.

Karl is notable for his repudiation of the inductivist approach to science, instead favoring the empirical falsification approach that empirical science theories can only be falsified, not proven. Karl made significant contributions in the quest to come up with solutions to the problem of demarcation, offering a clear standard for distinguishing between science and non-science, scientific theory and mythological claims. Karl’s works had massive influence both within and outside of the philosophy of science.

He is also known for his works on the fields of probability and quantum mechanics.

Quotes from the book The Logic of Scientific Discovery

“For myself, I am interested in science and in philosophy only because I want to learn something about the riddle of the world in which we live, and the riddle of man’s knowledge of that world. And I believe that only a revival of interest in these riddles can save the sciences and philosophy from an obscurantist faith in the expert’s special skill and in his personal knowledge and authority.”


“But I shall certainly admit a system as empirical or scientific only if it is capable of being tested by experience. These considerations suggest that not the verifiability but the falsifiability of a system is to be taken as a criterion of demarcation. In other words: I shall not require of a scientific system that it shall be capable of being singled out, once and for all, in a positive sense; but I shall require that its logical form shall be such that it can be singled out, by means of empirical tests, in a negative sense: it must be possible for an empirical scientific system to be refuted by experience.”

“I think that we shall have to get accustomed to the idea that we must not look upon science as a ‘body of knowledge,’ but rather as a system of hypotheses; that is to say, as a system of guesses or anticipations which in principle cannot be justified, but with which we work as long as they stand up to tests, and of which we are never justified in saying that we know they are ‘true’ or ‘more or less certain’ or even ‘probable.’”

“Again, we cannot search the whole world in order to make sure that nothing exists which the law forbids. Nevertheless, both kinds of strict statements, strictly existential and strictly universal, are in principle empirically decidable, each, however, in one way only: they are unilaterally decidable. Whenever it is found that something exists here or there, a strictly existential statement may thereby be verified, or a universal one falsified.”

“It is not his possession of knowledge, of irrefutable truth, that makes the man of science, but his persistent and recklessly critical quest for truth.”

“Those among us who are unwilling to expose their ideas to the hazard of refutation do not take part in the scientific game.”

Praise for the book

The book has received a lot of praise from scientists, philosophers as well as average, everyday readers.

“Popper enjoys a reputation as the greatest philosopher of the 20th Century. This book, in which he elucidated the doctrine of falsification still espoused by prominent scientific commentators like Richard Dawkins and endorsed by most scientists, went a long way to establishing that reputation. I would go so far as to say that you cannot understand a keystone in the philosophy of science without reading this work.”

“The best and most lucid description of the scientific method. The scientific method as it is understood today has been very closely associated with philosopher Karl Popper and his followers.”

“Popper presents a convincing refutation of scientism in this book. Arguing that the act of hypothesis formation is inherently a-logical, he characterizes the realm and function of science through ideas of demarcation and falsifiability.”

“An elegant although highly idealistic response to Hume’s problem of induction.”

“Extremely interesting… In particular, I really found his arguments on falsifiability’s role in science, and the role of probability in science thought provoking.”

The book is an interesting and thought provoking read for those interested in the fields of natural and social science.

You can grab your very own copy of The Logic of Scientific Discovery here!