Was Popper an emotivist/radical existentialist?

I am trying to assess to what extent were Popper is committed to a sort of “emotivism” or non-cognitivism, the view according to which calling a moral norm or standard “good” or “just” does not amount to a statement of fact, but to expressing some emotion or inclination of the will. Or, alternatively, to some form of “radical existentialism”, the view according to which all ultimate normative questions are a matter of ultimate existential choice, which cannot be based on further reasons.

From:
the open society and its enemies.

"Norms are man-made in the sense that we must blame nobody but ourselves for them; neither nature, nor God. It is our business to improve them as much as we can, if we find that they are objectionable. This last remark implies that by describing norms as conventional, I do not mean that they must be arbitrary, or that one set of normative laws will do just as well as another.

By saying that some systems of laws can be improved, that some laws may be better than others, I rather imply that we can compare the existing normative laws (or social  institutions) with some standard norms which we have decided are worthy of being realized."


Volume 1, ch. 5 "nature and convention". II
p. 67

[It is not easy to understand what Popper means. The use of the expression which I underline suggests that he endorses some form of emotivism or radical existentialism as defined above.

Further explications in the lines which follow the quoted passage:]

“But even these standards are of our making in the sense that our decision in favour of them is our own decision, and that we alone carry the responsibility for adopting them.”

[This is a thesis about the moral responsibility of adopting a standard. I assume that “responsible” means “morally responsible”, that is, “potentially blame/praiseworthy”. We can evaluate standards (e.g. standards of conduct) as either good or bad, just or unjust. Popper seems to be worried that, if we postulate the existence of moral facts about the goodness or justice of standards, this would threaten our responsibility for acting in conformity to the principle or standard we have decided to adopt. But this can only be true if one presupposes the implausible conjunction of the two following principles, namely 1. that we are not morally responsible for the act that follows from the correct application of a standard that we are not free to choose; 2. that we are not free to choose the standard that we find to be best or most just, because we cannot intentionally choose a standard that we regard to be morally worse, or more unjust, than some other alternative standard. More about this in the concluding remarks.]

“The standards are not to be found in nature. Nature consists of facts and of regularities, and is in itself neither moral nor immoral.”

[Of course standards are not found in nature, in the same sense as tables and chairs are, i.e. we do not “bump” into them. But this is trivial. The real question is does Popper mean that standards cannot be judged (as good or bad, just or unjust) objectively? Probably, Popper would argue that only we, human persons, and only we, can judge a standard as good or just and for that reason decide to use it to guide our action, and therefore have a sort of moral responsibility for making such judgments. But the problem is: what makes our judgments concerning what standards to use right or wrong? If we say: “a further standard”, we shift the question one step further, and we provide no real answer. Therefore Popper's position faces a dilemma: either he endorses a sort of emotivism, or he must admit that what justifies our ultimate standard is some “fact” prior to our will, so that we cannot be held responsible for it. This fact could be a fact about human nature or human rationality (which might be a-priori as Kant's categorical imperative), or a non-natural fact of Moorian kind. However it cannot be conceived as something that we invent or establish, and for which we can be held responsible.]

“It is we who impose our standards upon nature, and who in this way introduce morals into the natural world⁴, in spite of the fact that we are part of this world.”

[Here Popper seems to endorse an emotivist (or expressivist, or projectivist) position as standardly formulated in contemporary handbooks of analytic meta-ethics.]

“We are products of nature, but nature has made us together with our power of altering the world, of foreseeing and of planning for the future, and of making far-reaching decisions for which we are morally responsible. Yet responsibility, decisions, enter the world of nature only with us.”

[This is a non sequitur. Of course responsibility enters the world of nature only with us, in so far as we are the only being on Earth which can be regarded as agents in the full sense. And moral responsibility requires the fact of agency, and – if you wish, in addition to it – the fact of freedom of the will. But why should this fact support the idea that “we impose our standards upon nature” or that we “introduce morals into the natural world”, if that is taken to imply the idea that there is no standard of right or wrong, no truth in the moral sense, apart from our decisions (existentialism) or emotions (emotivism)? It seems to me obvious that moral objectivity (the idea that there are standards of right or wrong which do not depend from our arbitrary decisions or attitudes about what is right or wrong) or even cognitivism (the idea that the validity of standards of right and wrong can be discovered) or even realism (the idea that standards of right and wrong precede human decisions or attitudes in general) or even extreme realism (the idea that there are standards of right or wrong that exist independently from the existence of human agents) are all compatible with granting human beings full responsibility for their actions, in so far as they are in full possession of the agential qualities, and in so far as they are free to choose whether to act, or not to act, for the sake of what is good or right.]

Notice finally that Popper rejects emotivism in the notes corresponding to those passages, but I cannot see how he can escape the charge of defending either a form of emotivism or a form of radical existentialism. And the two views are quite similar, as it has been pointed out.