I am a long-time Karl Popper fan. I've read all but, I believe, 4 books of his. To my knowledge, this is his shortest at 161 pages - all consisting of essays. This is also the book of his that is the least original. If you're a long-time fan, you've read these ideas before. If you are a newcomer, there are better books to start with.
For all that, the first essay, "The Logic and Evolution of Scientific Theory" is the best short summary of Popper's views on science that I've read. The second essay is also a good summary of Popper's theories of body/mind interactionism, an odd position for a modern theoriest to hold.
The second half, although quite unoriginal (I've started to realize that Popper's views on freedom, democracy, open society, etc. were better expressed by James Madison)is still quite interesting. Also, this book, I'm quite sure for the first time, gives us Popper's views towards international policy. 'Waging Wars for Peace', an excerpt from a radio interview, is pretty timely in 2003 and reminds us that there can be no thing as an absolute pacifist. Not destroying someone certain to kill only postpones. The title essay, at 6 pages, is another timely celebration of technology; timely because many on the right and left (for different reasons about different techonologies) are preaching against technologies while failing to see the many good sides.
All in all, a quick and fairly worthwhile read. The experienced reader of Popper, again, will find nothing new here. [...]

I bought this a long time ago and it has languished on the to-read list. It is probably not the best introduction to Popper, but it's not bad.

The first section is a collection of speeches that have a lot of duplication between them. The good side of that is that I have a pretty good grasp of what he meant by a priori knowledge and his view of the scientific method. By a priori knowledge he means a set of expectations (either in the form of theory and hypothesis or, at a lower level, biological adaptation to the environment) that must be confirmed through interaction with the environment. His repeated comment is that Einstein can actually seek to refute his theories in the interest of advancing knowledge, but an amoeba must fear refutation since it will mean its own death to not be adapted properly.

The section on history and politics can probably be summed up as:
1) History is not a progression that we can really predict. One statement he makes is that history ends right now and the future is not predictable.
2) Be optimistic about the present - life is better now than it ever has been (at least on average).
3) We must constantly work to make the future better.
4) There is no guarantee that freedom will continue in the future as it has in the past. The longer people are free, the more they take it for granted and guard it less.
5) The real cause of a lot of conflicts in the modern world is over-population.

He was also amazingly pro-American for a European intellectual. He did not deny that we have problems but repeatedly stressed that we (the whole world of democracies and the US in particular) are the most successful form of social organization ever tried.

He also contradicts the common belief (originated, I believe with Bertrand Russell) that we are too smart scientifically and not smart enough morally. Instead, he suggests that people are very anxious to do the right thing and behave morally but are not smart enough to be able to judge the true effects likely to result from courses of action suggested by those who claim to be moral guides.

Originally, I wasn't going to recommend this book but I do because it is an easy read and a good introduction to what I understand to be most of Popper's main points.

Interesting read.

Bought this as a gift- he seems to enjoy it but felt like there were other books that needed to be read before or as companions.

Perhaps a good place to start in this review of "All Life Is Problem Solving" is to focus on one essay, "Towards an Evolutionary Theory of Knowledge" written in 1989.

Karl Popper (b.1902, d.1994) elegantly proposes that knowledge is linked to expectations. These expectations express theories of reality. Thus knowledge expresses theories of reality. We as with all living things have propensities to guess reality based on hypotheses which logically and psychologically precede observation. Encounters with evidence are the bumps that allow continual reformulation of these assumptions. This in no way implies that the universe separate from our perceptions is illusion. Indeed only fools or sophists would deny its existence, but what is the foundation for defining a "real" world? What is the real you? What is the real anything - statistically analyzed, dissected, named, viewed under an electron microscope, blasted with x rays or gamma rays, painted by Monet? If we open any dictionary on the word "knowledge" we find all sorts of circularity and assumptions that knowledge is primarily empirically derived. Popper's association of knowledge with expectation, or guessing, is a breakthrough in clarity. Animals and plants carry what can be defined as unconscious guesses or theories, namely their genes and other molecular and physiological codes. It is a world of propensities.

Despite perceptual and cognitive limitations, living beings do seek truth and routinely test models against assumed facts. Truth should correspond with facts, but the degree of certainty of facts varies. Popper's attitude to the demarcation of science from other intellectual endeavours is that scientific enquiry should have no expectation of reaching a destination of final truth but rather it is about asking things about the universe in such a way that any answer is capable of being modified (indeed capable of being falsified) if better evidence appears. Every answer is provisional. Scientism, which positively declares truths, is not science..."scientifically proven" is a nonsense phrase that is unfortunately commonly used by laypersons and academics alike and distorts the value of the scientific method. Indeed, including and beyond science, all our knowledge is uncertain. Scientific testing corroborates our tentative theories it does not confirm them.

Still at least in our universe, the world is roughly spherical even though many of our forefathers assumed that it was flat. The theory of evolution is similarly robust even if fine details have varying certainty. Thus some assumptions seem to be less wrong than others, i.e. have higher verisimilitude or truth likeness. Still, the demarcation of science and non-science hinges on phrasing any claim in such a way that it can potentially be proven wrong, not turned into an accretion of supporting premises that is unbreakable simply because it is amorphous. On this point it does not matter by which source the claim is reached e.g. inspiration might occur in a reverie, but rather how the hypothesis is expressed when presented to an audience. On a side note, I think too much criticism of Popper has been a sidetracked discussion of second-hand and often misattributed references rather than simply addressing his ethical challenge of making method accountable. This is unfortunate as it masks the value of demarcation in defending science against dogmatism. Creationism and intelligent design arguments tend to be accretions of self-supporting dogma rather than a critical discourse. On a personal note I would suggest that a corollary of Popper's thought is not cynicism but an attitude of openness to the unexpected. In narrow conceit, cynics overlook the corollary to the unprovable nature of reality namely that, precisely because we cannot prove otherwise, there is always room for surprises. Perhaps meaning cannot be demonstrated in a deterministic world i.e. it is not to be found in Schopenhauer's "World as Representation" but rather in the unexpected, the coincidental, the "World as Will". Popper stressed, unlike the logical positivists, that meaning can be found in unscientific statements. The search for truth (as a regulatory principle) hinges on inter-subjective criticism, not the shielding of our claims from refutation.

Excessive expressions of certainty are bred from protesting too loudly. The universe is mysterious, we do not need to invent mystery unless we want to couple spiritual sentiment to social power and we should not fear that honest engagement will destroy mystery. There is much to surprise us. Even the prevailing metaphors in cosmology will have their used-by date. Any statement of belief should be capable of being modified or indeed discarded if the facts contradict it, but this does not mean that well-tested ideas should be let go lightly.

Karl Popper distinguished between tacit knowledge and objective knowledge. We know there is a physical world (World 1), we know there is a mental world (tacit, World 2), and we know there is a world of codes and descriptions and formulae (World 3). Even when individuals die, worlds 1 and 3 still exist.

Let us give Popper the last word: "I shall now try to give you a list of interesting conclusions that we can draw, and partly have drawn (although so far unconsciously) from our trivial proposition that animals can know something............"

A Guide to The Logic of Scientific Discovery (The Popular Popper)
World of Propensities