Questions tagged [propositions]
The propositions tag has no usage guidance.
82
questions
3
votes
2
answers
143
views
Analyticity and a priority
(1) Every bachelor is unmarried.
I know this is one of the most famous examples (intensionally) denoting analytic and a priori propositions. No problems yet.
(2) Every apple is a fruit.
This one ...
- 33
2
votes
1
answer
66
views
A set of three statements, of which only two at a time can be true: is there a specific term for this type of combination game?
Here's two examples of what I'm talking about
1
An ideal citizen would be smart, ethical and politically engaged.
However, what usually happens in reality is this:
If they're smart ...
- 23
4
votes
4
answers
637
views
Can one have propositional knowledge without knowing the corresponding proposition?
The concept of propositional knowledge -- knowledge that one has through holding a justified belief in a proposition that states a fact -- is a foundational one in epistemology (for example, it is ...
- 326
1
vote
2
answers
231
views
Confused about the answers to two logic problems
True or False? If monkeys can fly, then 1 + 1 = 3.
What is logically equivalent to all x (p(x) + ~q(x))?
For the first one I think it is False.
- 35
0
votes
1
answer
2k
views
How to make the statement "If A or B then C" More Rigorous?
Suppose that I say the following,
If A or B then C
It is clear what happens if only A is true, if only B is true, or if neither A nor B are true.
However, what happens if both A & B are true? ...
- 109
2
votes
0
answers
58
views
How did Aristotelian logic view this?
I am very interested in the logical aspect of Aristotelian philosophy, especially how it was used by al Farabi and Ibn Sina in explaining understanding and breaking this complicated process down ...
- 197
1
vote
0
answers
46
views
partial fictionalism about propositions
One theory of propositions is that they're "useful fictions." However, this faces the formidable objection that fictionalism makes it hard to explain how something fictional can tell us about the ...
- 395
1
vote
0
answers
164
views
If logical propositions aren't tautologies (a la Wittgenstein), then what could they be?
This is a historical question about philosophical views. I believe I understand the claim made by Wittgenstein and others that logical propositions are tautologies. I'd like to know what other views ...
- 363
7
votes
1
answer
561
views
Is the principle of non-contradiction self-evident?
The principle of non-contradiction is that contradictory propositions cannot both be true, e. g. the two propositions "A is B" and "A is not B" are mutually exclusive.
However, whenever something is ...
- 408
2
votes
1
answer
476
views
How does a truth tree provide positive and negative effect tests for implication?
I'm trying to prove that the truth-tree method can be used to give a positive effect test for implication, and a negative effect test for non-implication. I've been given the fact that The truth-tree ...
- 21
2
votes
0
answers
115
views
Why don't two equivalent propositions contribute to the same semantics?
We often have 2 propositions that have the same truth table, in that they are true and false given the same conditions.
Nevertheless, we still feel as though there different semantics (i.e meaning..),...
- 2,419
0
votes
4
answers
181
views
On Truth and Lying
If A, consciously, reports false data to B, and B (or anyone else) has no way to verify, then no one can make the statement, "A lied". So, there exists no such person with respect to whom A lied.
...
- 1,139
8
votes
2
answers
860
views
Existential import: in logic, do propositions default to true or false when objects in them do not exist?
In this hypothetical:
Firefighters always tell the truth, while politicians always tell lies.
Suppose three people, who are either a mix of firefighters and politicians, all politicians, or all ...
- 233
2
votes
4
answers
4k
views
Why is questioning everything around us so important?
I've heard something disturbing from my friend. He said he's grateful to his father because his father taught him to question everything that was around us.
Why is this so important?
2
votes
3
answers
221
views
Understanding multiple values in a single cell of a truth table (P v ~Q) as (1 1 0 1) when P and Q are 1
This might seem basic to most here but I am struggling with a truth table for a disjunct. As I am looking at it further, I actually think the issue I am struggling with how to interpret truth values ...
- 479