Abstract: As opposed to the dismissive attitude toward reductionism that remains popular in philosophy of mind and cognitive science, a "ruthless reductionism" is alive and thriving in "molecular and cellular cognition"-a field within neuroscience's current cellular and molecular mainstream. Experimental practices and emerging results from this field imply that two common assertions by philosophers and cognitive scientists are false: (1) that we don't know much about how the brain works, and (2) that lower-level neuroscience can't explain cognition and complex behavior directly. These experimental practices involve intervening directly with molecular components of sub-cellular and gene expression pathways in neurons and then measuring specific behaviors. The behaviors are tracked using tests that are widely accepted by experimental psychologists to study the psychological phenomenon at issue (e.g., memory, attention, perception). I'll illustrate these practices and make explicit the accounts of explanation and reduction they employ based upon some details from recent experiments on mammalian contextual and social recognition memory.