Is 7 - 9 equal to 7 - 9?

Answer 1

To give an answer we first have to know what "truth" is. There are many theories about what is the "truth". I'm only going to cover the correspondence, coherence and consensus theories of truth and answer only in informations that are correct/true now (9th of December 2011 Central European Time).

Correspondence theory states, that the truth corresponds (fits) to the actual state of affairs.

That being said, 7 - 9 equals 7 - 9 if the actual state of affairs (in this case math rules and basic logic) say, that 7 - 9 equal 7 - 9.

That means, that 7 - 9 does equal 7 - 9.

Coherence theory states, that the truth is true, if it isn't in conflict with other truths.

That means, that 7 - 9 equals 7 - 9 if it isn't with conflict all other familiar equations equal the same equations (for example 8 - 10 equals 8 - 10; 7 - 7 equals 7 - 7).

That also means, that 7 - 9 does equal 7 - 9.

Consensus theory states, that the truth is whatever is agreed upon (or might be agreed upon) by a specified group.

That means, that 7 - 9 equals 7 - 9 if the group of people you (or I?) live with agrees, that 7 - 9 equals 7 - 9.

I/Group of people I live with agree that 7 - 9 does equal 7 - 9 and therefore

7 - 9 does equal 7 - 9 and if you disagree then you shall be anything from being ignored to being killed.

Answer 2

63

Answer 3

-16