The phrase "a certain proposition" is correct and usable in written English.
It can be used when referring to a specific idea or statement that is not explicitly named or defined.
Example: "In the context of our discussion, we must consider a certain proposition that challenges our current understanding of the theory."
Alternatives: "a specific statement" or "a particular claim".
(2) "If the fact that a certain proposition p implies some arbitrary proposition q implies that p itself is true, then p is (indeed) true".
If it is logically impossible for a certain proposition, p, to be true without a certain proposition, q, being also true (i.e., if the conjunction of p and not-q is logically impossible), then it is said that p strictly implies q.
In some ways, they have a point: an estimate of the number of scientists who agree with a certain proposition can only ever be a proxy for the underlying scientific knowledge.
Postulation is viewed as the sort of process by which one may come to know for certain the truth of a certain proposition, and yet the Bhattas refused to include such cases under inference on the grounds that in such cases one does not say to himself "I am inferring" but rather says "I am postulating".
If the recommendation were enacted by the court and upheld on appeal -- far from a certain proposition in both cases -- it would be one of the few times in the 110-year history of the Sherman Antitrust Act that the government had succeeded in breaking up a major national corporation.
Semantically, it expresses that a certain proposition is true at some accessible world.
Should Pohl rule in favor of additional disclosure, the CIA must decide if it will comply with the order – a less certain proposition for a military tribunal than for a civilian judge.
The second case argued Monday, Comcast v. Behrend, No. 11-864, was a less certain proposition in that regard, with several justices expressing a sort of buyer's remorse about how the case had reached the court.
This formula states that "if one proposition implies a second one, and a certain third proposition is true, then if either that third proposition is false or the first is true, the second is true".
But suppose there were someone with an unusual psychology such that whenever he understood a certain contingent proposition, such as "there are more females than males on Gliese 581d", it would immediately seem true to him.
Unlike many Christians who treat their faith as a system of certain propositions, Polkinghorne believes that the most authentic faith -- the one he finds in the Bible -- co-exists with doubt.
