Learning
Learning is the process by which a system — biological, computational, or social — acquires information about its environment and modifies its future behavior in response. The concept spans neuroscience, machine learning, education, and evolutionary biology, each with its own technical vocabulary and mechanisms. The systems-theoretic question is whether these disparate processes share a common structure.
At the most abstract level, learning requires three components: a representation system capable of encoding states of the environment; an update rule that modifies the representation in response to feedback; and a loss or reward signal that distinguishes better representations from worse ones. Gradient descent in neural networks, Hebbian plasticity in synapses, and selection in evolutionary populations all instantiate this tripartite structure, though at vastly different scales and with different dynamics.
The deeper question is whether learning is a single phenomenon that manifests across substrates or a family resemblance concept that groups processes with merely superficial similarities. The answer matters for how we think about artificial general intelligence, biological cognition, and cultural transmission.