Human microbiome research makes causal connections between entire microbial communities and a wide array of traits that range from physiological diseases to psychological states. To evaluate these causal claims, we first examine a well-known single-microbe causal explanation: of Helicobacter pylori causing ulcers. This apparently straightforward causal explanation is not so simple, however. It does not achieve a key explanatory standard in microbiology, of Koch’s postulates, which rely on manipulations of single-microorganism cultures to infer causal relationships to disease. When Koch’s postulates (...) are framed by an interventionist causal framework, it is clearer what the H. pylori explanation achieves and where its explanatory strengths lie. After assessing this ‘simple’, single-microbe case, we apply the interventionist framework to two key areas of microbiome research, in which obesity and mental health states are purportedly explained by microbiomes. Despite the experimental data available, interventionist criteria for explanation show that many of the causal claims generated by microbiome research are weak or misleading. We focus on the stability, specificity and proportionality of proposed microbiome causal explanations, and evaluate how effectively these dimensions of causal explanation are achieved in some promising avenues of research. We suggest some conceptual and explanatory strategies to improve how causal claims about microbiomes are made. (shrink)

Functional neuroimaging (NI) technologies like Positron Emission Tomography and functional Magnetic Resonance Imaging (fMRI) have revolutionized neuroscience, and provide crucial tools to link cognitive psychology and traditional neuroscientific models. A growing discipline of 'neurophilosophy' brings fMRI evidence to bear on traditional philosophical issues such as weakness of will, moral psychology, rational choice, social interaction, free will, and consciousness. NI has also attracted critical attention from psychologists and from philosophers of science. I review debates over the evidential status of fMRI, including (...) the differences between brain scans and ordinary images, the legitimacy of forward inference and reverse inference, and deductive versus probabilistic accounts of NI evidence. I conclude with a discussion of fMRI as exploratory rather than confirmatory evidence, linking this debate to the growing literature on cognitive ontology. (shrink)

In behavioral ecology some authors regard the innateness concept as irretrievably confused whilst others take it to refer to adaptations. In cognitive psychology, however, whether traits are 'innate' is regarded as a significant question and is often the subject of heated debate. Several philosophers have tried to define innateness with the intention of making sense of its use in cognitive psychology. In contrast, I argue that the concept is irretrievably confused. The vernacular innateness concept represents a key aspect of 'folkbiology', (...) namely, the explanatory strategy that psychologists and cognitive anthropologists have labeled 'folk essentialism'. Folk essentialism is inimical to Darwinism, and both Darwin and the founders of the modern synthesis struggled to overcome this way of thinking about living systems. Because the vernacular concept of innateness is part of folkbiology, attempts to define it more adequately are unlikely to succeed, making it preferable to introduce new, neutral terms for the various, related notions that are needed to understand cognitive development. (shrink)

Human microbiome research makes causal connections between entire microbial communities and a wide array of traits that range from physiological diseases to psychological states. To evaluate these causal claims, we first examine a well-known single-microbe causal explanation: of Helicobacter pylori causing ulcers. This apparently straightforward causal explanation is not so simple, however. It does not achieve a key explanatory standard in microbiology, of Koch’s postulates, which rely on manipulations of single-microorganism cultures to infer causal relationships to disease. When Koch’s postulates (...) are framed by an interventionist causal framework, it is clearer what the H. pylori explanation achieves and where its explanatory strengths lie. After assessing this ‘simple’, single-microbe case, we apply the interventionist framework to two key areas of microbiome research, in which obesity and mental health states are purportedly explained by microbiomes. Despite the experimental data available, interventionist criteria for explanation show that many of the causal claims generated by microbiome research are weak or misleading. We focus on the stability, specificity and proportionality of proposed microbiome causal explanations, and evaluate how effectively these dimensions of causal explanation are achieved in some promising avenues of research. We suggest some conceptual and explanatory strategies to improve how causal claims about microbiomes are made. (shrink)

Human microbiome research makes causal connections between entire microbial communities and a wide array of traits that range from physiological diseases to psychological states. To evaluate these causal claims, we first examine a well-known single-microbe causal explanation: of Helicobacter pylori causing ulcers. This apparently straightforward causal explanation is not so simple, however. It does not achieve a key explanatory standard in microbiology, of Koch’s postulates, which rely on manipulations of single-microorganism cultures to infer causal relationships to disease. When Koch’s postulates (...) are framed by an interventionist causal framework, it is clearer what the H. pylori explanation achieves and where its explanatory strengths lie. After assessing this ‘simple’, single-microbe case, we apply the interventionist framework to two key areas of microbiome research, in which obesity and mental health states are purportedly explained by microbiomes. Despite the experimental data available, interventionist criteria for explanation show that many of the causal claims generated by microbiome research are weak or misleading. We focus on the stability, specificity and proportionality of proposed microbiome causal explanations, and evaluate how effectively these dimensions of causal explanation are achieved in some promising avenues of research. We suggest some conceptual and explanatory strategies to improve how causal claims about microbiomes are made. (shrink)

In behavioral ecology some authors regard the innateness concept as irretrievably confused whilst others take it to refer to adaptations. In cognitive psychology, however, whether traits are 'innate' is regarded as a significant question and is often the subject of heated debate. Several philosophers have tried to define innateness with the intention of making sense of its use in cognitive psychology. In contrast, I argue that the concept is irretrievably confused. The vernacular innateness concept represents a key aspect of 'folkbiology', (...) namely, the explanatory strategy that psychologists and cognitive anthropologists have labeled 'folk essentialism'. Folk essentialism is inimical to Darwinism, and both Darwin and the founders of the modern synthesis struggled to overcome this way of thinking about living systems. Because the vernacular concept of innateness is part of folkbiology, attempts to define it more adequately are unlikely to succeed, making it preferable to introduce new, neutral terms for the various, related notions that are needed to understand cognitive development. (shrink)

The amygdala is a key brain area regulating responses to stress and emotional stimuli, so improving our understanding of how it is regulated could offer novel strategies for treating disturbances in emotion regulation. As we review here, a growing body of evidence indicates that the gut microbiota may contribute to a range of amygdala-dependent brain functions from pain sensitivity to social behavior, emotion regulation, and therefore, psychiatric health. In addition, it appears that the microbiota is necessary for normal development of (...) the amygdala at both the structural and functional levels. While further investigations are needed to elucidate the exact mechanisms of microbiota-to-amygdala communication, ultimately, this work raises the intriguing possibility that the gut microbiota may become a viable treatment target in disorders associated with amygdala dysregulation, including visceral pain, post-traumatic stress disorder, and beyond. Also see the video abstract here: https://youtu.be/O5gvxVJjX18 The amygdala plays a central role in regulating many aspects of behavior in rodents and humans, from pain responding to social interaction and psychiatric function. Accumulating evidence suggests microbiota-to-amygdala communication along the gut-brain axis is a key modulator of these amygdala-dependent behaviors, with critical implications for health and disease. (shrink)