In his System of Logic (1843), he developed a thoroughly empiricist theory of knowledge and of scientific reasoning, going even so far as to regard logic and mathematics as empirical (though very general) sciences.
As a result of such claims it was widely believed that any results obtained by logicians or ethicists must at best be treated as provisional; followers of Hegel, who advanced these claims with passionate conviction, were inclined in consequence to regard logic and ethics alike as minor branches of philosophy.
Ramus thus regarded logic as a part of philosophy and defined it as an art that truly gives us knowledge of being.
He regarded logic as having an unhealthy influence ("unheilvollen Einflüss") on mathematics ("Für den Cantorismus, aber gegen den Russellismus" is the final motto of Schönflies 1911).
Most Neoplatonists followed Alexander of Aphrodisias in regarding logic not as a separate philosophical discipline (the Stoic view) but rather as philosophy's tool, its organon.
In addition to the general attitude to scientific philosophizing that he derived from Twardowski, there is one identifiable source of some other of Łukasiewicz's philosophical stances regarding logic, or if not a source, at least a point of convergent convictions.
In this and other regards, informal logic has significant affinities with the "pragamatic logic" movement one finds within the Polish logical tradition (see Koszowy 2010).
As regards the logic of the argument, all of the steps in the argument, other than the inference from (1) to (2), are deductive, and are either clearly valid as they stand, or could be made so by trivial expansions of the argument at the relevant points.
An interesting point regards the logic circuits created by Boolean functions and its dynamics.
The study of proposition forms, however, cannot be similarly accommodated under the study of inference forms, and so for reasons of comprehensiveness it is usual to regard formal logic as the study of proposition forms.
