Sophistical syllogism offers the appearance of proof while relying on illusory premises or false claims dressed up as credible propositions. Estimation extends sensible properties to non-sensible matters without warrant; deceptive premises borrow similarity in wording or meaning.
The book also differentiates sophistry from contentious wrangling. Such arguments have no intrinsic epistemic value, though recognizing them brings an indirect protective benefit. A corrupt syllogism may fail in matter, form or both.
The next independent section, asbāb al-ghalaṭ (causes of error), examines specific sources of confusion, especially failure to distinguish a thing from what resembles it.