Laws of Reasoning

The principle of sufficient reason

states that everything (whether it is a thing, an event, or a proposition) must have a reason or a cause.

A example of The principle of sufficient reason

1. For every entity X, if X exists, then there is a sufficient explanation for why X exists.
2. For every event E, if E occurs, then there is a sufficient explanation for why E occurs.
3. For every proposition P, if P is true, then there is a sufficient explanation for why P is true.

The law of identity

The law of identity states that a is a

The law of identity example

For example a dog is a dog, a dog is not a cat.

The law of non-contradiction

states that a proposition cannot be true and false at the same time.

Example of the law of non contradiction

So, for example, if you believe that "Today is Wednesday" and Today is not Wednesday" at the same time (Eastern Standard) and in the same respect (not "Today is Wednesday, but it sure feels like Tuesday"), then you hold a contradiction.

The law of the excluded middle

states that a specific proposition is either true or false. There is no middle ground, such as sort of true or neither true nor false.

The law of the excluded middle example

The proposition may be true on July 23, 2010, In Toronto, Ontario, but false at the same time in North Bay, Ontario. The proposition could be false in the same place in Toronto but on different data, such as July 24, 2010.

Ockham’s Razor

The simplest explanation or theory is the best choice. The simplest explanation is the one that makes the fewest assumptions and uses the fewest entities to explain the same facts.