The doctrine that the content of the conclusion of a deductively valid argument is included in the content of its premises, taken jointly, is a familiar one. It has important consequences for the question of what value valid arguments possess, since it indicates the poverty of three traditional answers: that arguments may and should be used as instruments of persuasion, that they may and should be used as instruments of justification; and that they may and should be used to advance knowledge. The truth is, however, that in each of these cases the argument has only a managerial role and, if there is any work done, it is the premises that do it. It will be maintained that this point has little force against the critical rationalist answer, which I shall defend, that the principal purpose of deductive reasoning from an assemblage of premises is the exploration of their content, facilitating their criticism and rejection. That said, the main aim of the present paper is not to promote critical rationalism but to consider some published objections to the doctrine that a statement asserts every statement that is validly deducible from it. The alleged counterexamples to be considered fall roughly into two groups: statements that emerge with time from a rich mathematical or empirical theory, but were originally unformulated and are deducible from the theory only in a non-trivial way (Frederick 2011, 2014; Williamson 2012); and statements, notably disjunctions, that are easily formulated and are deducible from a theory in a trivial way (Schurz & Weingartner 1987; Mura 1990, 2008; Gemes 1994; Yablo 2014). Each of these counterexamples will be evaluated and dismissed.

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We introduce a new formal logic, called equality propositional logic. It has two basic connectives, ^ (conjunction) and ≡ (equivalence). Moreover, the ⇒ (implication) connective can be derived as A ⇒ B: = (A ^ B) ≡ A. We formulate the equality propositional logic and demonstrate that the resulting logic has reasonable properties such as Modus Ponens(MP) rule, Hypothetical Syllogism(HS) rule and completeness, etc. Especially, we provide two ways to prove the completeness of this logic system. We also introduce two extensions of equality propositional logic. The first one is involutive equality propositional logic, which is equality propositional logic with double negation. The second one adds prelinearity which is rich enough to enjoy the strong completeness property. Finally, we introduce additional connective Δ (delta) in equality propositional logic and demonstrate that the resulting logic holds soundness and completeness.

This study examined the establishment of coherence relations by Persian EFL learners in their reading of stories.201 undergraduate EFL learners read narrative passages and selected appropriate coherence elements of different types necessary for the proper construction of meaning. The results demonstrated a consistent pattern of a text-specific hierarchy for the comprehension of conjunctive relations across learners with different proficiency levels. More specifically, adversatives were found to be the easiest connectors by all the three groups followed by causals as the second easiest, then sequentials as the third and more difficult, and additives as the most difficult markers. The results have both theoretical and practical applications and implications for the ‘model building’ hypotheses on the one hand, and reading comprehension and instruction on the other.

The nature of Propositional knowledge is of important issues in contemporary epistemology. The common theory of epistemologists, knows propositional knowledge as "justified true belief", but this view encountered the problem called “Gettier problem ". The contemporary epistemologists caused a fundamental rethink with the concept of knowledge and different approaches, based on Gettier criticism on the tripartite analysis of knowledge. This essay seeks to extract theory of Propositional knowledge sadr-ol-mote’allehin to correspond to contemporary epistemology approaches through review of 'knowledge' issue in transcendent theosophy (Hikmah Muta’liyah). Sadra's theory of Propositional knowledge is multifaceted theory; an aspect of epistemic and cognitive function. He not only does not reduce knowledge to propositional knowledge alone, but also he considers it as an aspect of cognitive function. Knowledge of recent aspect affecting on subject. He does not limit to a way achieving knowledge by one method, rather with high attitude, knows effective in achieving knowledge of all faculties, knowledge and moral virtues, divine faculty even God.