To investigate the effect of weed interference and weed-free periods on Balangu (Lallemantia royleana Benth. in Wall) and to evaluate the Critical period of weed control (CPWC) in this oilseed crop, an experiment was conducted as a randomized complete block design with three replications in Naghadeh region in 2018. Experimental consisted of two groups of treatments; weed infestation treatments (infestation for 144.2, 345.9, 574, 848.2, 1147.6 and 1451.3 growing degree day (GDD) after transplanting and then plots were remained weed-free the rest of the growing season) and weed-free treatments (weeding for 144.2, 345.9, 574, 848.2, 1147.6 and 1451.3 GDD after transplanting and then plots were remained infested until harvesting time). In each block, one weed free and weed infested control was for all the growing season. Results indicated that the density and dry biomass of weeds were increased as weed removal was delayed. In contrast, density and dry biomass of weeds were decreased as weeds establishment was delayed. Height, tetrachenes fruits, ripened achenes, 1000-seed weight and biological, seed and relative yields of Balangu were decreased and increased as the duration of weed-infested and weed-free period increased, respectively. Also, logistic and Gompertz curves fitted to data showed that the beginning and end of the CPWC based on a 10% yield loss of relative yield, was estimated to be from 11 to 108 days after transplanting (97 days weed-free period) in order to prevent a noticeable yield loss.

In this paper, I address the issue of the possible applicability of the ideas of Karl R. Popper’s social and political philosophy in the contemporary political life of postcolonial countries. Through reference to the reception of Popper’s philosophy in Central and Eastern Europe, I argue that Popper’s writings were effective in catalysing the political wholesale transformation by undermining Marxists’ pretensions to scientific status rather than through his anti-utopian and anti-revolutionary political recommendations. In the context of attempts to apply Popper’s ideas in postcolonial countries, especially Sub-Saharan Africa, I claim that the influence of Popper’s social thought on the politics of those countries may not be as effective as expected or desired.

The aim of this paper is to consider whether Critical rationalism has any ideas which could usefully be applied to the internet.  Today we tend to take the internet for granted and it is easy to forget that it was only about two decades ago that it began to be used to any significant extent. Accordingly in section 1 of the paper, there is a brief consideration of the history of the internet.  At first sight this makes it looks implausible that any of Popper’s ideas could be applicable to the internet, since Popper died before the internet came into general use.  However, section 2 argues that Popper’s theory of World 3 does apply very well to the internet.  This application is significant because, as shown in section 3, it leads to the problem of misinformation, which is one of the most significant problems generated by the internet.  In section 4 there is an attempt to solve this problem using ideas taken from Popper’s epistemology. It is argued that there should be changes in education designed to prepare students for the internet age. Teaching in the internet age should focus on presenting to the students not just the accepted theories but also the evidence on which they are based. An illustration of how this might be done is given by considering an example from science teaching, namely the teaching of Newtonian mechanics in the last years of school or first years of university.

'Post-truth' has become a buzzword for numerous current crises: the fragmentation of the media landscape, the ongoing debate about 'fake news', the loss of trust in science, etc. Although these crises take place in society, it is claimed that the roots of post-truth can be traced back to the history of philosophy. Occasionally, it is asserted that Karl Popper's Critical rationalism gave rise to post-truth: His rejection of verificationism has limited truth claims in the realm of science. Given the absence of infallible evidence and certainty, Critical rationalism calls for challenging scientific authority. I argue that post-truth is compatible with Critical rationalism from an epistemological point of view, considering that both positions are Critical of certainty. However, in Critical rationalism, fallibilism, responsibility, and the idea of criticism are combined, and in this respect, it offers a possible way to overcome the problems that are associated with post-truth. This treatment of the problems of post-truth results from the recognition of moral responsibility to take action on the basis of a hypothesis that remains open to revision.

Since Critical Rationalism is considered by some more of an attitude or mindset and by others a methodological approach to philosophical thinking and practical problem-solving, its application, or more accurately, its epistemological testing grounds, should be expected to be much more wide-ranging than they have been so far. With the exception of some published anthologies on Critical Rationalism and occasional nods to the legacy of Karl Popper’s falsificationist methodology, relatively few applicaions of a Critical rational approach to contemporary theoretical debates in the social sciences have been published. I wish here to Critically challenge the (optimistic) Hegelian and by extension the neoliberal view of the progress of American capitalism by reframing it with the Marxian notion of expropriation as applied to enslavement on plantations. The logic of enslavement as a process by which brutal exploitation has been practiced for centuries offers a falsifying test case of the rationality of capitalism and its promise of individual freedom of choice. This essay is an explicit exercise in the potential power of a version of Popperian Critical rationalism being applied to the intersection of modern liberalism and capitalism, exploring the imbrication of a Critical and rational analysis.

Artifacts are ubiquitous and influential in our world, but their nature and existence are controversial. Several theories have been proposed to explain the ontology of artifacts. Drawing on Popper's theory of three worlds, this paper suggests a metaphysics for artifacts along the line of a Critical rationalist (CR) approach. This theory distinguishes between three realms of reality: the physical world (World 1), the mental world (World 2), and the world of objective knowledge (World 3). The paper argues that artifacts have different ontological components that correspond to these three realms, and that each component is real and causal. The paper shows how this perspective can account for the intentional and functional aspects of artifacts, as well as their dependence on plans that influence different realms of reality. The paper explains how this pluralistic ontology, compared to the rival theories, enables one to explain the relevant ontological problems of artifacts. The paper also explores how this proposal can lead to a research program encompassing a broader range of technologies, such as social artifacts. In sum, the paper suggests that Popper's three worlds theory provides a rich and comprehensive framework for understanding the metaphysics of artifacts.