 Several other philosophers have also taken up the case of the mesosome. Allchin (2000) characterizes the initial evidence for the mesosome as robust and describes how subsequent research showing how particles were generated by degeneration of the membrane in preparation for electron microscopy led to a reassessment, culminating in mesosomes being recognized as artifacts. Weber (2005) argues that the process of evaluating claims about artifacts employs causal reasoning of the same sort as used in testing theoretical hypotheses. According to him, mesosomes were judged to be artifacts when evidence supported the claim that they were produced by chemical fixation. Hudson (2014: chapter 2) advances yet another alternative: according to which what mattered most to researchers was whether they regarded the process for generating evidence for or against mesosomes as a reliable process.