Related Experiment Video
Updated: Aug 17, 2026

The Innovation Arena: A Method for Comparing Innovative Problem-Solving Across Groups
Published on: May 13, 2022
A commentary on the Zinkernagel-Hengartner 'Credo 2004'
1Conceptual Immunology Group, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA. cohn@salk.edu
Abstract:
In 'Credo 2004', Zinkernagel and Hengartner give us a food-for-thought analysis of immune responsiveness based on a 'pragmatic and empiric point of view.' The Credo 2004 postulates derived by inductive extrapolation from observation to generalization do not satisfactorily account for immune behaviour because they lack a conceptualization as illustrated here. Nevertheless, Credo 2004 is certainly valuable in a limited framework because it is based on the most likely of assumptions namely that the immune system was evolutionarily selected to protect against infectious agents, and therefore the study of pathogens will most accurately reveal how the immune system responds normally to protect. After reformulating them, the postulates of Credo 2004 are analysed with respect to their generality.
Related Concept Videos
Ziegler–Natta Chain-Growth Polymerization: Overview
The Aufbau Principle and Hund's Rule
Empathy
Zener Diodes
Kirchhoff's Rules
Kirchhoff's first rule is called the junction rule. A junction, also known as a node, is a connection of three or more wires. The rule states that the sum of all currents entering a junction must equal the sum of all currents leaving the junction.
Hess's Law

