For the introduction to this series click here.

For the first part of this series, click here.

For the second part of this series, click here.

Man is the only metaphysical animal.–William James, Principles of Psychology

One of the premises of this blog is that the laws of thought and logic are properties of being, or reality. Not all logicians hold to this view but it is the position, I think, which corresponds most closely to reality. This post is related to our previous post on the principle of existence (the undeniable principle that being is). As we have seen, a principle is that which something else in its order follows. For example, in order to perform calculations correctly, one must first understand the underlying principles and axioms of mathematics. Principles are the foundation of any science and every other human activity.

The principle we come to now, in our explication of the argument from being (click here if you want a condensed form of it), is the principle of identity.

The principle of identity is simply that being is identical to being, or a thing is identical to itself. A thing is what it is. In a syllogism, the middle term must always have the same meaning and not be equivocal (undergo a change of meaning) in order to be valid. When it comes to reality, the law of identity applies when we are talking about dogs with the understanding that we are discussing animals which belong to the class of canines and not fish, hamsters, or monkeys. My cat cannot be a cephalopod. By virtue of it being a cat, and having all the properties a cat has, it cannot be another species or something else. Anything that exists at all is identical to itself and not to another. A thing can be similar to another (analogically or perhaps metaphorically) but it cannot be univocally the same. The law of identity states that A is A. As we will discover later, the law of identity is related to the law of noncontradiction (A cannot be non-A in the same sense and same relationship.) At the very basic and fundamental level of reality, we all know that there is a difference between A and non-A. A must be A, a thing is what it is.

What might the principle of identity have to do with cosmological reasoning? The answer is that it is a basic property of reality. The principle of identity is true of the cosmos (it does exist, it is what it is) and of every thing within it. It is one of the principles and axioms of reality.

Furthermore, it is an undeniable principle of reality. To say that A is not identical to A assumes that each A is identical. It is self-refuting to deny the principle of identity.

The principle of existence and the principle of identity are important aspects of reality. The truth is, we use these concepts everyday. Being is the most fundamental and basic idea to our existence. Dr. Mortimer Adler, explains it this way,

… You and I and everybody else uses the word ‘exists’ or ‘is’—there’s no commoner word in any language than the ontological predicate ‘is’ or ‘is not’—you and I day in and day out say that is or that does not exist, and when we say something does not exist we are thinking of nothing in its place sometimes. So I think the concept of being and not being or existence and nothingness are, shall I say, part of the very heart of human thinking. (36)

Indeed, the principles of existence and identity are essential to human thinking about reality. It is absolutely impossible to deny that being is. This establishes our first premise in our cosmological argument.

In our next post we will apply the law of noncontradiction to cosmological reasoning.

Works cited

Dzugan, Ken, editor. How to Prove There Is a God: Mortimer J. Adler’s Writings and Thoughts about God. Open Court, 2012