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This paper engages with Isaac Levi's approach to justifying changes in our states of full belief and offers a Peircean criticism of his strategy for resolving conflicts between the results of what inquirers deem to be the most reliable programs for a given situation and the settled beliefs about which we have no doubts. In the first section, I discuss the central features of Levi's theory of justifying changes to our state of full belief. In the second section, I present a Peircean approach to evaluating the reliability of these programs for routine expansion of belief, and I argue that there is a conflict between Levi's approach to situations where an inquirer has expanded her beliefs into inconsistency and Peirce's criticisms of non-scientific methods for settling opinion. The third section presents two potential objections to the Peircean approach, objections that emphasize the importance of our concern to avoid error, and in the fourth section, I propose an original supplement to the Peircean approach that better addresses that concern. Ultimately, my aim is to develop and defend a Peircean approach that is in opposition to Levi's views about when it is appropriate to question the reliability of our programs for routine expansion of belief but that also addresses his legitimate worries about underemphasizing our concern to avoid error. [ABSTRACT FROM AUTHOR]

Haploid myxamoeboid mating types, CR5-11A11 and HON 1-2A1, of the acellular myxomycete Didymium iridis, were isolated and grown in liquid culture. Previously it has been postulated that a molecule, possibly a hormone, is responsible for the induction of mating competency through receptor site synthesis. The intention of this study was to isolate the molecule and to determine its mode of action. Experiments were designed in order to learn whether it acts only upon the cells which produce it (self-induction) or does it have an effect only on opposite mating types (cross-induction). It was found that plasmodia can only form on solid media, although zygotes are readily formed in liquid media. Moreover, competency of cells to fuse, or to form receptors required that they be haploid and in a specific phase of the cell cycle, namely G1 of interphase. The use of high pressure liquid chromatography techniques was also employed in order to investigate the inducer molecule. It was demonstrated that the inducer molecule was similarly produced by both mating types, and its production was essentially paralleled by cell numbers. It was also discovered that mating competency is self-induced and these results are discussed.