Rationality, for Popper, is to be identified with openness to criticism; and each individual is to be valued a s a source of possible criticism. Objectivity, rather than being regarded as the attribute of the particular, wise individual is regarded as a social product – a product of critical discussion. 
It is important for the understanding of this attitude to realize that these decisions can never be derived from facts (or from statements of facts), although they pertain to facts. The decision, for instance, to oppose slavery does not depend upon the fact that all men are born free and equal, and that no man is born in chains. For even if all were born free, some men might perhaps try to put others in chains, and they may even believe that they ought to put them in chains. And conversely, even if men were born in chains, many of us might demand the removal of these chains. Or to put this matter more precisely, if we consider a fact as alterable—such as the fact that many people are suffering from diseases—then we can always adopt a number of different attitudes towards this fact: more especially, we can decide to make an attempt to alter it; or we can decide to resist any such attempt; or we can decide not to take action at all.
All moral decisions pertain in this way to some fact or other, especially to some fact of social life, and all (alterable) facts of social life can give rise to many different decisions. Which shows that the decisions can never be derivable from these facts, or from a description of these facts. [ch. 5, 67]
Earlier I said that Popper believed in absolute and objective truth. This is very easily misunderstood, especially if we equate a definition of ‘truth’ with a criterion of truth. But whether or not truth is absolute has nothing whatsoever to do with whether or not we have a criterion for determining what it is. ‘Absolute’ simply means that something is not conditional or relative to anything else. Popper thought that truth is absolute in just this sense. Being true is different from being-believed-to-be true. It is not relative to or conditioned by what anyone believes. And it does not depend upon a theory, or evidence, or a historical context, or anything else—except the facts. 
No doubt the idea which inspires the inductive style—the idea of adhering strictly to the observed facts and of excluding bias and prejudice—is laudable. And no doubt those trained to write in this way are unaware that this laudable and apparently safe idea is itself the mistaken result of a prejudice—worse still, of a philosophical prejudice—and of a mistaken theory of objectivity. (Objectivity is not the result of disinterested and unprejudiced observation. Objectivity, and also unbiased observation, are the result of criticism, including the criticism of observational reports. For we cannot avoid or suppress our theories, or prevent them from influencing our observations; yet we can try to recognize them as hypotheses and to formulate them explicitly, so that they may be criticized.)