  In virtue of their material nature, particulars are extended, mutable, and subject to generation and destruction. How then is the materiality of the particular related to the characterization for which participation is responsible? What materiality induces is that a property be manifested in a specific way. So, when we consider a particular stick to ask what is its length, we expect to be told a specific quantity: the stick is five inches long. The same is true of its weight: it is six ounces. If we are concerned to explain why the stick is that long, one answer is that the matter of the particular compels it to have determinate  length.[15]  Only when we shift to the question ‘What is length?’, do we begin to reflect upon the relations between length and the fact that each of these material particulars has a specific length. In the Meno (74ff), Plato develops the notion of determinable and determinate. There the properties themselves are determinates falling under a determinable, e.g., crimson and scarlet under red, red under color. Now, the properties under consideration are all generic or determinable, but when present in the particular they take on a specific, determinate character. Consider, for instance, mathematical figures. The Triangle itself will be a three-sided figure whose lines lack breadth and whose angles have no determinate degree. But all particular triangles will have lines with some breadth and angles with certain  degrees.[16]  There is, then, a gap between the non-specific and non-determinate property and the way it is manifested in the particular. The immaterial Form of Triangle is abstract and can have no particular dimension. The property in the particular, on the other hand, must be specific and determinate—the property in the particular is always a specific, determinate length, or color (hue), or size, or so on—because the particular is concrete, and because the property in the particular is itself a particular instance of the non-determinate property.