a fortiori argument an argument that moves from the premises that everything which possesses (a) certain characteristic(s) will possess some further characteristic(s) and that certain things possess the relevant characteristic(s) to an eminent degree to the conclusion that a fortiori (even more so) these things will possess the further characteristic(s). The second premise is often left implicit, so a fortiori arguments are often enthymemes. An example of an a fortiori argument can be found in Plato’s Crito: We owe gratitude and respect to our parents and so should do nothing to harm them. Athenians owe even greater gratitude and respect to the laws of Athens and so a fortiori should do nothing to harm those laws. See also ENTHYMEME, SYL- LOGIS. R.P.