'As outlined in Part I, in positing vibratory bodily perception in opposition to what he characterized as ‘cinematographic’ mechanical observation Bergson was implicitly investing in a current of psycho-physiological science that had gained considerable traction during the final decades of the nineteenth century. Critically, as well as articulating a conception of life as adhering to different laws as those believed to govern non-living nature, this current of thought helped elevate a category (or rather set of categories) of psychological existence that had historically been conceived of as obstacles to thought (affective states) to the status of epistemic primacy. Thus, where previous thinkers had conceived of passions or emotions (on the transition between these categories see Dixon 2003) as either problems to be overcome by observers or (as in the Kantian tradition) as aspects of experience to be balanced by rational comprehension, Bergson made them foundational to his philosophy.'