Degenerate is a tricky term...

The more ways a system can achieve a function, the more robust and adaptable it becomes.

I think it is fair to say we tend to think of “degenerate” as a pejorative. Something broken, collapsing, or inferior.

But in complex systems — biological, neural, or artificial — degeneracy means something far more interesting: different structures performing similar functions.

It is not a redundant structure, though provides a similar feature if the primary structure fails.

Key references

• Degeneracy (biology) — “the ability of structurally different components to perform similar (but not necessarily identical) functions in different contexts”. ([Wikipedia][1])
• Edelman & Gally (2001) “Degeneracy and complexity in biological systems” — outline degeneracy as a feature of biological complexity, robustness, evolvability. ([PMC][2])
• Tononi, Sporns & Edelman (1999) “Measures of degeneracy and redundancy in biological networks” — formalises how structurally different elements yield same function. ([PNAS][3])
• Whitacre (2010) “Degeneracy: A design principle for achieving robustness…” — argues degeneracy enables systems to adapt and maintain function under perturbation. ([ScienceDirect][4])
• In systems biology / neuroscience: “Brain’s Best Kept Secret: Degeneracy” (2023) — “Different processes or structures leading to the same result”. ([PMC][5])
• More recently: Roy et al. (2023) arXiv “Interplay of degeneracy and non-degeneracy in fluctuations propagation…” — applying degeneracy concepts in network motifs. ([arXiv][6])