James Ladyman has argued that constructive empiricism entails modal realism, and that this renders constructive empiricism untenable. We maintain that constructive empiricism is compatible with modal nominalism. Although the central term ‘observable’ has been analyzed in terms of counterfactuals, and in general counterfactuals do not have objective truth conditions, the property of being observable is not a modal property, and hence there are objective, non‐modal facts about what is observable. Both modal nominalism and constructive empiricism require clarification in the face of...

James Ladyman has argued that constructive empiricism entails modal realism, and that this renders constructive empiricism untenable. We maintain that constructive empiricism is compatible with modal nominalism. Although the central term ‘observable’ has been analyzed in terms of counterfactuals, and in general counterfactuals do not have objective truth conditions, the property of being observable is not a modal property, and hence there are objective, non‐modal facts about what is observable. Both modal nominalism and constructive empiricism require clarification in the face of Ladyman's argument. But we also argue that, even if Ladyman were right that constructive empiricism entails modal realism, this would not be a problem for constructive empiricism.

1 Introduction

2 Concerning (A) ‘The entire view is stated in modal discourse’

3 Concerning (B) ‘The central term “observable” is a modal term’

3.1 A devastating argument?

3.2 Critique of the argument

4 The objectivity of ‘observable’

4.1 A specific empirical question

4.2 Viewing ourselves as our own measuring instruments

5 Concerning (C) ‘Scientific theories involve irreducible modality’

6 Serious tension at the motivational level?