In the philosophy of science classical rationalism equates rationality with proof and proof with Truth.

What is the meaning of rather 'critical rationalism'? Is it the view advocated by Popper by which rationality is no more than criticism as opposed to'proof'? If so, does critical rationalism give up Truth? Or does it give up certainty only? If he only gives up certainty but does not give up Truth, how does it still reach Truth?

  • A simple google search for "critical rationalism stanford" gave the answer within seconds. I cannot see any effort answering the question yourself.
    – Philip Klöcking
    Commented Nov 30, 2015 at 8:30
  • 6
    I vote for "Leave open". The question asks more than just to pigeonhole criticial rationlism. The issues truth, certainty, and proof are legitime philosophical points.
    – Jo Wehler
    Commented Nov 30, 2015 at 8:58

2 Answers 2


Critical rationalism is the view propagated by Popper.

Popper does not give up the concept of truth.

His first point is, that we cannot prove general theorems in science, because we always have only finitely many observations. The next observation could refute the statement. Hence Popper gives up proving general theorems in science.

According to Popper our scientific theorems are hypotheses. One should create hypotheses which are testable. A test can confirm or refute a hypothesis. In the latter case, the hypothesis is false and we need a better hypothesis. But even a confirmed hypothesis is not proved. We do not know whether it is true. Hence Popper replaces proof by falsifcation.

By eliminating false hypotheses we hope to approach truth, which is considered a limit term. Pointedly formulated by Gerhard Vollmer: "We err upwards."

Certainty is the personal feeling to have true knowledge. It is a subjectice term and does not guarantee truth.

  • Thanks a lot! You have clarified exactly the point in Popper's view of which I was confused. Commented Nov 30, 2015 at 11:04
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    I understand now then that according to Popper truth is not guaranteed but only hoped for, and that truth cannot be guaranteed because he replaces proof by falsification and in turn he can only tell of a theory that it is false in case it was refuted or falsified, and hope that better theory would be "closer" to truth (?). Thanks again. Commented Nov 30, 2015 at 11:12
  • You are right. - I consider Popper's turn to be a revolution in philosophy :-)
    – Jo Wehler
    Commented Nov 30, 2015 at 12:02
  • Appreciate your responses. - Popper now sounds to me interesting and intriguing (much more than Thomas Kuhn who my teachers seem to prefer lecturing about). Thanks :-) Commented Nov 30, 2015 at 12:23
  • How does the idea that “the next observation could refute the statement” mesh with theorems understood best as explaining mean effects? For example, if I hold that the average gymnast is shorter than the average basketball player, one observation (discordant pair) clearly does not refute the theorem.
    – Todd D
    Commented Jul 20, 2020 at 14:59

Critical rationalism holds that there is objective truth and it is possible for people to learn about it. You learn about how the world works by making guesses and then criticising the guesses. You never have any guarantee that you have reached the truth although you may make progress toward it through critical discussion.

Most epistemologists make a lot of fuss about certainty, but this is largely irrelevant to making progress. What is relevant to making progress is getting rid of bad ideas and proposing replacements that fix the flaws in your previous ideas.

The focus on certainty has done a lot of damage to epistemology leading to a lot of subjectivist nonsense. For an extended discussion of this problem, see "Realism and the Aim of Science" by Popper, Chapter I. Other material worth reading on critical rationalism includes "On the sources of knowledge and of ignorance" in Popper's book "Conjectures and Refutations", the title essay in Popper's book "The Myth of the Framework", as well as chapters 3 and 7 in "The Fabric of Reality" by David Deutsch.

If you are interested in discussing Popper further with people who have deep knowledge of Popper, you may want to consider the Fallible Ideas discussion group.

  • Thanks a lot for this elaboration, suggestion and reading-recommendation. Commented Dec 1, 2015 at 5:34

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