Full Idea
The case of atoms makes it clear that the indispensable appearance of an entity in our best scientific theory is not generally enough to convince scientists that it is real.
Gist of Idea
The theoretical indispensability of atoms did not at first convince scientists that they were real
Source
Penelope Maddy (Naturalism in Mathematics [1997], II.6)
Book Reference
Maddy,Penelope: 'Naturalism in Mathematics' [OUP 2000], p.143
A Reaction
She refers to the period between Dalton and Einstein, when theories were full of atoms, but there was strong reluctance to actually say that they existed, until the direct evidence was incontrovertable. Nice point.