4.3 Logical relations between sentences

1. The truth conditions of two sentences may be related to each other in various ways

2. 4.3.1 Logical entailment

2.1. In easy words it is the relasionship that intels one sentences with other just for simple logic due to the truth value.it can be non-Symmetric.

2.2. A. Donald Duck is a duck. B. Donald Duck is a bird.

2.3. A.El pato Donald es un pato.  B, El pato Donald es un ave.

3. 4.3.2 Logical equivalence

3.1. It happens when 2 sentences have identical truth conditions and it is symmetric so , it's equivalence is a mutual entailment

3.2. A The bottle is half empty.   B The bottle is half full.

3.3. A. La botella esta medio llena.  B. La botella esta medio vacía.

4. 4.3.3 Logical contrariety

4.1. Also Known as logical exclucion or incompatibility., it focuses on falsity

4.2. A) Today is Monday..             B )Tomorrow is Wednesday. A) Hoy es Lunes.                   B) Mañana es Viernes.

4.3. Two contrary sentences cannot both be true but they may both be false