Sunday, 8 February 2015

A Defence of Two Basic Principles (Part II)

Sorry that it's been so long, you can partly blame health and partly my lack of focus.

Last time I blogged, I made an introductory post on the Principle of Sufficient Reason (PSR) and Principle of Causality (PC) and outlined where I intended to go. I said that my approach would be to start by considering the nature of axioms and then to attempt to establish that the PSR and PC should be considered axioms. For this post, I will attempt the first of these tasks (explaining what axioms are); my next post will attempt to make the case that the PSR and PC are axiomatic.

What are Axioms?

The basic function of logic and argument is to get from premises to conclusions. For example, if we start with the premises "All men are mortal" and "Socrates is a man" we can reach the conclusion "Socrates is mortal." Often, in a complex argument, our premises will be the conclusions from an earlier set premises. This process raises the question of where our first and original set of premises comes from.

These first premises are, in logic and maths, commonly called 'axioms'. Some philosophers use the term 'properly basic beliefs'. Axioms can't be proven in the ordinary way because, as I said, they are the original premises which all subsequent arguments depend on.

Common examples of what are often considered axioms, certainly things treated as axioms by Thomists, include the three laws of logic famously formulated by Aristotle ie. The laws of Identity, Non-Contradiction and the Excluded Middle.

Are Axioms Reliable?

Since axioms can't, in the ordinary sense, be proven, it might appear that they are arbitrary and that we can't have good reason for believing them true. I disagree. My position (I claim no originality here) is that there are axioms which we can know are true.

Thomists and other Aristotelians have traditionally argued that certain axioms are self evident. However, since many people have asserted that all sorts of things are self evident, there is an argument that helps establish the reliability of genuine axioms.  Put simply a principle can be regarded as axiomatic and true if that principle is such that it needs to be presumed for any knowledge to be possible and/or if the principle must be invoked to argue against it.

An example will illustrate my point. I once got into an argument with someone who argued that the basic laws of logic have no objective basis. His argument went as follows: "If the laws of logic had objective basis the development that we have seen in the sciences would not have happened. The development that we have seen in the sciences has, however, obviously happened, therefore the laws of logic have no objective basis."

Obviously his opening premise is highly debatable, but his argument has a more serious flaw than that. In making his argument, he was himself invoking the Law of Non-Contradiction. This is a basic point commonly found with Aristotle's basic laws, any attempt to argue against them necessarily invokes these laws, thus assuming their validity. This, for Thomists, helps to underscore the self evidence truth of these laws.

Some, of course, will object that while this demonstrates the necessity of such axioms for human thought, it proves nothing about their objective validity. The argument may go that, yes, for human thinking to work, we must assume these axioms are true, but that gives no reason to think they correspond to any objective reality.

On this view, mathematics, logic, and the like, which all depend on these basic laws, are not necessarily connected to anything objectively verifiable but simply the working out of what follows necessarily from these axioms which are, as it happens, necessary for human thought.

I would point out, in response, that if these laws have no objective validity, then we can't even know what follows from them. We might say that "If the Law of Non Contradiction is True then it follows that 2+2 = 4 can't be both true and false." But in saying this we assume the validity of that Law. If these basic axioms are not true, then the whole edifice must collapse, being built on sand.

If these axioms are not reliable, we can't even know that we have no good reason to believe them because that conclusion is it's self based on reasoning based on these axioms; the argument "We only have good reason to believe the things for which evidence can be put forward, but no evidence can be put forward for these axioms" is based on the laws of identity and non-contradiction.

Put simply, these axioms are self evidently true and ought to be believed.

Wednesday, 14 January 2015

A Defence of Two Basic Principles (Part I)

Last year, I had the honour of debating Travis McKenna of the University of Sydney Atheist Society on the question of whether God exists. I had nothing particularly original to offer, I defended the argument, which St. Thomas calls the most evident, namely the argument from motion. Travis responded in a way which, I'll admit, caught me somewhat by surprise, in that he directed most of his criticism on a single point, namely the Principle of Causality. Since then, I've been intending to write a series of blog posts on Causality, and it's related principle, the Principle of Sufficient Reason.

The Principle of Causality (PC) and Principle of Sufficient Reason (PSR) were once generally accepted as basic rules of metaphysics. Since the time of the Scottish philosopher David Hume (1711-1776) however, they've been highly controversial. I shall be arguing, however, that they are reliable principles from which knowledge can be derived.

Definitions

St. Thomas defined the PC: "nothing can be reduced from potentiality to actuality, except by something in a state of actuality." While I like this definition, it has a certain amount of baggage in that it's tied to some Aristotelian views on potentiality and actuality. Since I want to keep the discussion here relatively focused, for the purposes of this series, my definition of the PC shall be "Whatever is changed in any way is changed by something other than its self."

The PSR, like the PC has been formulated in a variety of different ways. For  the purposes of this series, however, we can define the PSR as this: "Whatever exists has an explanation for its existence either in its own necessity or in some external cause."

For some these two principles may seem simple common sense after all, in our common experience, things don't generally pop into existence without explanation.  Philosophically, however, simple common sense  is not enough. Even if we could, simply accept these principles as matters of common sense in describing interactions between things in our world, that would be insufficient to  justify the use of such principles in arguments for God's existence. After all, the fact of these principles holding good in this universe wouldn't prove that they hold in relation to something outside of the universe.

This Series

What I hope to show with this series, however, is that the PC and PSR have more than just common sense and empirical data behind them but are necessary truths about all possible existence. My plan is to start by looking at the nature of an  axiom, then by examining why the PC and PSR should be considered axioms, then by looking at some common objection.