Full Idea
'That is red' in a context where the demonstrative fails to refer is truth-valueless, despite being meaningful, as is 'the queen of France in 2010 is bald'. ...The claim that some sentences are meaningful but truth-valueless is, then, widely accepted.
Gist of Idea
A sentence can be meaningful, and yet lack a truth value
Source
Ofra Magidor (Category Mistakes [2013], 4.1)
Book Reference
Magidor,Ofra: 'Category Mistakes' [OUP 2013], p.81
A Reaction
The lack of truth value is usually because of reference failure. It is best to say the words are meaningful, but no proposition is expressed.