Nadine de Courtenay is Associate Professor of History and Philosophy of Science at the Paris Diderot University & Laboratoire SPHERE, France.Olivier Darrigol is Research Director at CNRS & Laboratoire SPHERE, France.Oliver Schlaudt is Associate Professor of Philosophy of Science at Heidelberg University, Germany.

• 1. Introduction; 2. The origins of the Metre Convention, the SI and the development of modern metrology; 3. Justifying and motivating an SI for all people for all time; 4. Reforming the International System of Units: On our way to redefine the base units solely from fundamental constants and beyond; 5. Strategies for the definition of a system of units; 6. Relations between units and relations between quantities; 7. On the Conceptual Nature of the Physical Constants; 8. And how experiments Begin: The International Prototype Kilogram and the Planck Constant; 9. The SI and the Problem of Spatiotemporal Constancy

Nadine de Courtenay is Associate Professor of History and Philosophy of Science at the Paris Diderot University & Laboratoire SPHERE, France.Olivier Darrigol is Research Director at CNRS & Laboratoire SPHERE, France.Oliver Schlaudt is Associate Professor of Philosophy of Science at Heidelberg University, Germany.

• 1. Introduction; 2. The origins of the Metre Convention, the SI and the development of modern metrology; 3. Justifying and motivating an SI for all people for all time; 4. Reforming the International System of Units: On our way to redefine the base units solely from fundamental constants and beyond; 5. Strategies for the definition of a system of units; 6. Relations between units and relations between quantities; 7. On the Conceptual Nature of the Physical Constants; 8. And how experiments Begin: The International Prototype Kilogram and the Planck Constant; 9. The SI and the Problem of Spatiotemporal Constancy

Nadine de Courtenay is Associate Professor of History and Philosophy of Science at the Paris Diderot University & Laboratoire SPHERE, France.Olivier Darrigol is Research Director at CNRS & Laboratoire SPHERE, France.Oliver Schlaudt is Associate Professor of Philosophy of Science at Heidelberg University, Germany.

• 1. Introduction; 2. The origins of the Metre Convention, the SI and the development of modern metrology; 3. Justifying and motivating an SI for all people for all time; 4. Reforming the International System of Units: On our way to redefine the base units solely from fundamental constants and beyond; 5. Strategies for the definition of a system of units; 6. Relations between units and relations between quantities; 7. On the Conceptual Nature of the Physical Constants; 8. And how experiments Begin: The International Prototype Kilogram and the Planck Constant; 9. The SI and the Problem of Spatiotemporal Constancy