and practitioners of analogical reasoning agree that it must contain an attribute shared by the original case and the new case. This shared attribute is the universal. In syllogistic reasoning, however, one need not establish that the universal is instantiated in any particular case. One may simply say:

“Blackness and whiteness cannot coexist,” without specifying any particular blackness or whiteness.

Or one may say:

“The whole is greater than the part,” without specifying anything in particular.

Analogical reasoning, by contrast, requires a specific original case against which the new case is compared and to which it is likened. Thus one says:

“This blackness and this whiteness cannot coexist; the same applies to all other instances of blackness and whiteness.”

“This whole is greater than this part,” and so on.

Advocates of analogical reasoning say that this is more beneficial, because universals do not exist in concrete reality; they exist only in the mind. Comparing the new case to a particular established in external reality therefore yields knowledge of a specific existing thing, unlike a universal whose particular instances in external reality are not envisaged.

Hence, whenever someone discusses abstractly posited universals without conceiving of their particular instances in external reality, his discourse is either of little benefit—indeed, of none—or contains many errors and mistakes, or combines both shortcomings.

They also say that knowledge of each individual particular is acquired by the same means as knowledge of the particular