 According to Ortín Nadal (2019: 1129–1132), the fundamental difference between qualities of the two types is not that ideas of SQs provide more material for error; in perception, specific ideas of both sorts can misrepresent particular physical causes. They differ with regard to the mistakes we can make about their causes. To judge that a body resembles the sensation of a color is to error about the nature of matter, whereas to make an error about the determinate PQ of a particular object is still to know that it has the determinable quality it comes under.