Open Science Repository Philosophy

doi: 10.7392/OpenScienceRepository.Philosophy.2012.08191970

The actual philosophy of science of Karl Popper beyond all misunderstandings

The Open Science Repository

Abstract: The philosophy of science of Karl Popper is widely misunderstood and misrepresented. Many people do not read Karl Popper directly from his own works; instead, they read interpreters and commentators that have not read Popper’s original books and articles as well. The original philosophy of science of Karl Popper, however, is the most important piece of thought of the last century, and all those misunderstandings stand only for the delay of such recognition and the benefits that humankind can derive from it. In this work, the main points of Popper’s philosophy of science, presented by 41 theses logically concatenated, is summarized. Although this list can be considered an interpretation, it is an authentic attempt to describe his original ideas, learned from his multiple works.

Keywords: Karl Popper, philosophy of science, epistemology.

Full Text

Part 1 – The logic of science

I - With science we try to explain things we consider interesting or in need of explanation. Science is a way to solve problems of explanation.

II – In general, we know the things that we want to explain, and the desired explanations are unknown to us. Science therefore is the explanation of known things by unknown things.

III – When we explain something, we use two components: initial conditions and universal laws. These components together produce the final condition, which is the thing we are explaining.

IV – Universal laws are the main component of explanations. They try to describe the structural properties of reality.

V- Universal laws can, as well, be combined with different initial conditions and tested for the production of the predicted final conditions.

VI – Testing universal laws using different initials conditions means independent testing, the basis of scientific research. Scientific research is mostly independent testing of the combination of universal laws with initial conditions.

VII – The tests of universal laws are always attempts to refute the predictions based on the laws.

VIII – We can never be certain that a universal law is true, for it is an assertion supposed to be valid at every place in the universe and at every time: a counterexample is potentially possible to be found, somewhere or some time in the future.

IX – Since universal laws are always open to refutation, they are perpetually hypothetical for us. We can never know for certain whether they are true. (Incidentally, since even initial conditions are dependent on other universal laws, they are hypothetical as well.)

X – Although truth, regarded as a set composed of every actually true universal law and every initial condition possible, does exist, it is beyond human certainty.

XI – Scientific knowledge therefore is entirely and forever made of suppositions about what is truth; it is hypothetical knowledge.

Part 2 – The progress of science

XII – Newly discovered universal laws need themselves to be explained. Science then needs to dig deeper and deeper into the structure of reality, a never ending job.

Part 3 – The method of science

XIII – Science does not oppose mythology, religion and literature. Mythology, religion and literature also contain explanations of things considered in need of explanation. Science and these other branches of the human thought are built upon the very same problems.

XIV - Mythology, religion and literature can be considered preparation for science and, by no means, are antiscientific in nature. People go to churches or read poetry for the same motives they go to laboratories and do scientific research: to get in touch with real problems that challenge their minds.

XV – The difference between science and mythology, religion or literature is the scientific tradition of evaluating explanations critically. Explanations are, for science, hypotheses to be put under rational and, preferably, empirical scrutiny. Mythology, religion and literature consider their explanations either absolute truth, a matter of faith, or metaphors that direct attention and grant importance to the problems with which they deal.

XVI – The method of science is thus the critical evaluation of theories, guided by the idea of searching for truth.

XVII – Critical evaluation of newly proposed or established theories is done through logical appraisal (which means internal consistency and logical compatibility with everything else supposed to be true and related to the theory) and by, whenever possible, experimental tests.

XVIII – Through such critical evaluation, competing hypotheses, alternative solutions for the same problem, are compared: the weak ones are put aside and the better ones are kept as possibly valid or supposed to be true.

XIX - The disregard of hypotheses previously supposed to be true, by means of successful attempts to refute them, along with the discovery of –hypothetically- relevant, deep universal laws, means the progress of science.

Part 4 – The content of science

XX – Science is made of hypothetical descriptions of problems, theories and critical arguments.

XXI – Scientific knowledge is a set of hypothetical descriptions of problems, theories and critical arguments, including historical knowledge about problems, theories and arguments once supposed to be true but now replaced by other ones or disregarded as false.

XXII – Science is, in its main part, made of knowledge about our previous mistakes, the history of our errors.

XXIII – Since science is composed of linguistic descriptions, it is made of abstract objects; it is objective.

XXIV – An entire new real set of objective descriptions emerged with science. Karl Popper called this the “world 3”, in addition to the “world 1” of physical objects and the “world 2” of mental processes and states.

XXV – The objectivity of science is exemplified with the help of an imaginary situation: Even if humankind disappears, scientific knowledge, for example, stored in remaining computer memories, could potentially be deciphered by other intelligent beings; such potential of being deciphered by others than the ones who produced it stands for the objectivity of science.

XXVI – Just as honey is not attached to the bees that produce it, science is not subjective; it is an objective product of the human mind. It is, nevertheless, an objective product so important to humans as honey is to bees.

Part 5 – The psychology of science

XXVII – Humans do science using their creativity and ingenuity. Science is a creative activity just like art.

XXVIII – In science, creativity and ingenuity are used to discover relevant problems, produce new explanatory hypotheses and envisage ways of submitting existing theories to new scientific tests. This is what Einstein did, for example, and what has been done in the CERN LHC collider.

XXIX – Science is indeed a branch of the human arts: the one that includes tentative solutions for problems and their critical evaluation, everything guided by the idea of searching for truth. Scientists are artists too, and science is also an artistic achievement.

Part 6 – The sociology of science

XXX – In this part, the sociology of science, we have to mention what science is not, for it has been widely misrepresented in its social manifestations.

XXXI – Since the content of science is entirely hypothetical, there are no authorities in science. The idea of a scientific authority comes from the false belief that science produces undisputable truth.

XXXII – Because science is objective, it is not a realm of an elite of women and men called scientists. Scientific knowledge does not belong to brains; it belongs to books, research papers and other objective communications.

XXXIII – To be familiar with some relevant problems is indeed what differentiates scientists from others. Contributing to the progress of science, however, is not a task limited to scientists.

XXXIV – Since science is, in its main part, made of knowledge about errors; the discovery of errors in presently accepted or proposed theories is one of its challenges. Every human mind can contribute to such scientific challenge; it is not limited to scientists.

XXXV – Also, every human mind can contribute to the scientific challenge of imagining new theories. This task is not a privilege of scientists (or, instead, we can legitimately consider everyone who contributes as a scientist).

XXXVI – In order to foster the progress of science, there should be, except for moral limits, no barrier to the creativity and ingenuity that may come from anyone.

XXXVII - Specialization should not be a barrier for the progress of science. Scientists, scholars and students should contribute to diverse fields of science, not limiting their work to the fields in which they are specialists. Non-scientists should not be discouraged to contribute to any field.

XXXVIII – Financial barriers should not be placed between scientific knowledge and people. Scientific papers and communications should be available for everyone, regardless of payment.

XXXIX – The institutional organization of science should not be intricate and complex. In order to eliminate barriers between human minds and science, where the progress of science must mostly be stimulated, the proceedings of scientific organizations should be simplified. Bureaucratic and ritualistic complications should be systematically extirpated from science.

XL– Everyone should have the right to debate scientific ideas.

Part 7 – The aim of science

XLI – As stated in part 1, the aim of science is the discovery of structural properties of reality, of relevant universal laws. It is an infinite process, for the discovered laws need also to be explained, and so on. Theories about these properties are perpetually subject to error: they are hypothetical forever, even those most successfully tested.

XLII - Religion and art are both legitimate ways of immediate transcendence. Science is also legitimate, it is step-by-step transcendence.


Karl Popper books, listed in order of importance for this article:

“Objective Knowledge: An Evolutionary Approach”

“Conjectures and Refutations”

“The Logic of Scientific Discovery”

“Realism and the Aim of Science”

“In Search of a Better World: Lectures and Essays from Thirty Years”

“The Open Society and Its Enemies”

“Intellectual Autobiography”, also known as “Unended Quest: An Intellectual Autobiography”

“The Poverty of Historicism”

Each of them is a must-read for scientists.

Cite this paper


Oliveira, F. (2012). The actual philosophy of science of Karl Popper beyond all misunderstandings. Open Science Repository Philosophy, 1 (1), 1. Retrieved from


Oliveira, Francisco. “The actual philosophy of science of Karl Popper beyond all misunderstandings.” Open Science Repository Philosophy 1. 1 (2012) : 1.


Oliveira, Francisco. 2012. The actual philosophy of science of Karl Popper beyond all misunderstandings. Open Science Repository Philosophy 1, no. 1: 1.


Oliveira, F., 2012. The actual philosophy of science of Karl Popper beyond all misunderstandings. Open Science Repository Philosophy, 1(1), p.1. Available at:


1. F. Oliveira, Open Science Repository Philosophy 1, 1(2012).


1.Oliveira, F. The actual philosophy of science of Karl Popper beyond all misunderstandings. Open Science Repository 1, 1 (2012)


doi: 10.7392/OpenScienceRepository.Philosophy.2012.08191970