Laser Lights and Designer Drugs: New Techniques for Descending Levels of Mechanisms "in a Single Bound"?

Optogenetics and DREADDs (Designer Receptors Exclusively Activated by Designer Drugs) are important research tools in recent neurobiology. These tools allow unprecedented control over activity in specifically targeted neurons in behaving animals. Two approaches in philosophy of neuroscience, mechanism and ruthless reductionism, provide explicit accounts of experiments and results using tools like these, but each offers a different picture about how levels of mechanisms relate. I argue here that the ruthless reductionist's direct mind-to-cellular/molecular activities linkages "in a single bound" better fits with both the experimental designs using these tools and some of the scientists' own judgments about their results than does the mechanist's "nested hierarchies of mechanisms-within-mechanisms." So at least some important work in current neuroscience appears to be ruthlessly reductive. Mechanism may not correctly characterize all current work in neuroscience, despite its recent popularity.