The Analogy of Religion

Philosophy, Christian Theology, and Joseph Butler

Category: Posterior Analytics

I Just Know! Aristotle and Sense-perception

Aristotle, you will recall in yesterday’s post, has shown us one way of knowing something: through a demonstration or argument. This seems like a relatively straight forward way of knowing. However, Aristotle’s second way of knowing (which actually forms the foundations for demonstrations) is a little tricky to grasp, and probably far more controversial. In fact, in a few weeks time we shall explore Descartes’ attack on the broad idea of “Pre-existing knowledge”, which will probably make this idea of Aristotle’s easier to understand too. Let’s start with a phrase Aristotle writes near the beginning of his Posterior Analytics: “All teaching and all intellectual learning arises from pre-existing knowledge”

At first glance Aristotle appears to be following Plato’s lead by suggesting that all knowledge is pre-existing (see my earlier posts on the Meno). However, this is not an affirmation of innate knowledge; Aristotle certainly doesn’t mean that. What he means by pre-existent knowledge is knowledge which is “primary and immediate”; or, in other words, knowledge gained by an innate power or capacity. It is this capacity that gives us knowledge, for example, that “All men are moral”.

Why doesn’t Aristotle think that we have innate knowledge of true premises? He writes “it would be strange if we possessed [these starting-points] all along, since then we would possess knowledge superior to demonstration without being aware of it.” Nevertheless, Aristotle is aware of Meno’s paradox and the problem of coming to know something without pre-existing knowledge of it: “it is clearly impossible…..for us to acquire [these starting-points] if we are ignorant and have no predisposition for knowledge”.

His solution is “an innate power of discernment – what we call sense-perception”. For Aristotle, when we perceive particulars, such as a man called Bob, and then a man called Derek and then many other particular men, our memories retain these perceptions and forms what Aristotle calls “experience”. From this experience we now have a “universal” in our minds: the universal of man to be precise.

Let me put it another way: If we perceive a man called Bob, a “primitive universal” of man is in our minds, and if we continue to perceive particular men the universal of man is more and more firmly established in our minds. And this provides some of the knowledge that the premise “All men are mortal” is true. The objects of knowledge, then – the universals – are perceived by naturally noticing and remembering similarities between the particulars. The same would apply to the universal of women, the universal of potato…etc…

Finally, Aristotle says that this innate capacity to acquire pre-existing knowledge is more accurate and more sure than the scientific knowledge that proceeds from it. Aristotle says “there cannot be scientific knowledge of the starting-points…it is intuition that grasps the starting-points”. Or to point it another way: sense-perception, memory and the ability to gain knowledge of the universals cannot be demonstrated; these capacities are assumed to be true from the start.

We still don’t know much about this “intuition” and how it functions, but Aristotle’s’ key point is this: some knowledge you can’t prove with any argument or “demonstration”, but this knowledge is still more sure than the arguments which build on it.

In my next post – and leaping ahead hundreds of years in the history of ideas – I will explain how Descartes attempts to doubt these starting-points. Furthermore, he will try to demonstrate that they are true!

Does Aristotle’s idea of innate capacities solve Meno’s Paradox? What do you think about the idea of sure knowledge which doesn’t require an argument to believe?


Cold Hard Logic: Aristotle and Demonstrative Knowledge

Aristotle’s works, as I mentioned in my last post, were not written in the form of dialogues (any dialogues he did write have apparently been lost). Instead we have works that are very dense and technical, which makes Aristotle hard to read and understand. The Posterior Analytics is no different in this regard, but since it is a relatively short work it provides us with a useful introduction to Aristotle’s philosophy and a chance to hear some of  his ideas about the nature of knowledge.

We have already heard how Plato’s defined knowledge: he said that knowledge related to that which is. Plato, moreover, thought that the objects of knowledge are the immaterial, unchanging and eternal forms (remember the form of “absolute beauty”). The objects of everyday experience do participate in the forms, according to Plato, but they themselves are only the objects of opinion, not knowledge. Building on Plato, Aristotle also thinks that knowledge must relate to what is stable and unchanging: he writes “knowledge relates to what cannot be otherwise.” But Aristotle does not shared the contention that the objects of knowledge are the forms and he also denys that we have innate knowledge in the sense Plato expresses in the Meno. The reason for this will become apparent in the next post, but first we will briefly explore another element of Aristotle’s epistemology: demonstrative knowledge.

Demonstrative or Scientific knowledge

Aristotle describes two ways of knowing. The first is pre-existing knowledge and the second is through a demonstration. Take the following argument:

1. All men are mortal

2. Socrates is a man

3. Therefore, Socrates is mortal

For Aristotle, a “demonstration” is an argument with two characteristics. First, the premises need to be true. That ‘all men are mortal’ must be a true statement and that ‘Socrates is a man’, likewise, must be knowledge (remember knowledge and truth relate to “what cannot be otherwise”). If the argument is logically valid and the premises are true then the conclusion must be true too. Both characteristics seem to be fulfilled by the argument above. The following argument, however, is invalid, but it does have true premises:

1. All men are mortal

2. Socrates is an animal

3. Therefore, Socrates is mortal

Notice that the conclusion does not follow from the premises. In contrast,take this argument:

1. All men are purple

2. Socrates is a man

3. Therefore, Socrates is purple

The argument is valid (the conclusion follows from the premises), but one the premises is clearly not true.

Aristotle calls a valid argument with true premises a “scientific syllogism” and  the conclusion “scientific knowledge”. Now the word ‘science’ obviously has a specific modern meaning, but remember for Aristotle – writing before the advent of the modern scientific disciplines – the word refers to knowledge in this broader sense.

Demonstrative knowledge, then, is knowledge gained through a logical argument. But then another question arises: how do we know whether a premise, “All men are mortal”, in this example, is true? What are the starting points for knowledge which these premises are built on? With this in mind, I will explore Aristotle ideas about sense perception, memory and the building blocks of knowledge in my next post.

Does Aristotle’s two characteristics of a demonstration seem reasonable to you? Do you agree with Plato and Aristotle that knowledge must relate to that which is or what cannot be otherwise? Why does knowledge need to relate to stable objects?