- Sense data from the senses are turned by the mind into percepts which are conscious experiences of the environment
- The physiological states of animals are due to physical and chemical forces (not to vital energy)
- Perception and action are mediated by a process in the brain
- Perceptions are derived from unconscious inference on sense data
- Perceptions are mere hypotheses about the world
- All knowledge comes from experience
- Perceptions are hypotheses based on our knowledge.
- Knowledge is acquired from perceptions