Physical/implementation: How is the system physically realized (as neurons in a brain, transistors in a modern CPU &c)
Algorithmic/representational: How is the information processing system performing the operations, what are the representations/data structures, what is the “trace” of the algorithm
Computational: What problem does the system overcome, why does it overcome that problem.
These three to me seem to correspond eerily well to Dennett’s stances: physical stance↔physical/implementation level, design stance↔algorithmic/representational level, and intentional stance↔computational level.
I often feel like I want to add a fourth level to Marr’s hierarchy, treating the system as a black box and looking simply at outputs and inputs, perhaps one could call that the “functional” or “mapping” level.
Related: Marr’s Tri-Level Hypothesis, which offers three similar perspectives:
Physical/implementation: How is the system physically realized (as neurons in a brain, transistors in a modern CPU &c)
Algorithmic/representational: How is the information processing system performing the operations, what are the representations/data structures, what is the “trace” of the algorithm
Computational: What problem does the system overcome, why does it overcome that problem.
These three to me seem to correspond eerily well to Dennett’s stances: physical stance↔physical/implementation level, design stance↔algorithmic/representational level, and intentional stance↔computational level.
I often feel like I want to add a fourth level to Marr’s hierarchy, treating the system as a black box and looking simply at outputs and inputs, perhaps one could call that the “functional” or “mapping” level.