In Part One of the present text a philosophical characterization of common sense is presented, focusing first of all on its epistemological aspects. Part Two is devoted to these types of doubt or skepticism that may be defined as popular and do not require a philosophical background. Part Three is concerned with strictly philosophical skepticism, whose characterization and confrontation with common sense requires a general and introductory answer to the question about whatin fact philosophy is. In Part Four examples are presented of difficulties and antinomies to which confusing the level of commonsensical thinking with the level of philosophical thinking leads. The difficulties result from, on the one hand, attempts at solving philosophical problems by referring to popular intuitions, and, on the other, the willingness to infer consequences related to everyday life from philosophical deliberations. The disquisition seeks to justify the thesis that skepticism and undermining common sense – alien to popular thinking – belong to the nature of philosophy, and hence postulates to decide philosophical problems by referring to common sense, as well as charges sometimes leveled against philosophy that it does not give any actual solutions to practical problems should be regarded as misunderstandings.

In its suppositional phrasing the quantifier-less calculus of names has rules of introduction and Omission of the all (π) and some (σ) functors of the n/n category. The functors are the equivalents of quantifiers. A certain extension of its language by individual variables and a list Operator ([…]) is proposed here. In so extended language the quantifier-less calculus of names with lists is constructed, where axiom AI (a Substitute of the axiom of the theory of identity) and the rules characterising the list Operator are adopted.