Aristotle
Plato's theory of the Forms was not without its critics. In particular, Plato's student Aristotle was a vocal critic of the theory though not with the concept of form entirely. The questions Plato had raised and attempted to answer were worth pursuing and the concept of form was a valuable contribution. But from Aristotle's perspective, there were refinements needed in the theory. There were many criticisms that Aristotle put forward but for our purposes, we will discuss the three most important.
1. The third man problem
2. The problem of separation
3. The problem of accounting for change
1. To begin with, let's consider the claims made by Plato and see how Aristotle deals with them. Plato's theory claims to account for similarities among groups of objects. The Form explains our ability to see that different human beings (for example) are really examples of the same idea (the Form Human Being). Aristotle, however, disagrees. The only explanation Plato seems to give of the Form explaining similarity is that if you have two people (let's call them James and Jennifer) the Form Human Being will explain what it is that is similar about them.
Does the Form really do this? Aristotle says no and here's why. Suppose I pointed to James and Jennifer and asked whether you think they are similar. You may say yes (or you may say no) but you will probably want me to clarify what makes them similar. To do this, suppose I point to Paul and say that he explains what is similar about James and Jennifer. Have I really answered the question of similarity? It seems that I haven't. What I've done is raise another similarity that needs explaining, in this case, the similarity between the pair James and Jennifer, and Paul. In other words, all I have done is offer a third man to explain the original similarity. The problem is that the explanation doesn't do what it claims to do; it just adds more that needs explaining. This could go on forever! I could point to Shelly to explain the similarity between James/Jennifer and Paul but that wouldn't help either. This is the third man problem.
2. Again let's consider a claim Plato makes about the Forms. They are the cause of objects and our knowledge of them. OK, how does causality usually work? One thing causes another to happen but for this to occur the first thing must be in contact with the second. For example, if I say I am going to cause the lights to go out in the room, I need to turn off the light switch (or cut the power or something). In any case, I have to make contact with something to generate the effect of the lights going out. If I just stand there and say that I am going to cause the lights to go out, nothing happens. There must be contact between cause and effect.
But according to Plato the Forms and objects are NEVER in contact. Remember, the Forms are transcendent, so they are separate from the world of objects. So how could they be the cause of objects? Aristotle says that they couldn't. Unless... Here's where it’s important to remember that Aristotle does not completely dismiss the idea of form. He agrees with Plato that forms are a cause of objects. But Aristotle maintains that forms cannot be the cause if they are separate from the objects. Conclusion: Forms are not separate from the objects. Instead of postulating that the forms are transcendent, Aristotle says that they are imminent; that is they are in the objects themselves. Just as well, we have a hard enough time explaining things in this world without having to worry about a transcendent world of Forms! This insight, that Forms are in the object, has some important implications that we will come to in a moment.
3. The problem of accounting for change may be the most damaging to Plato's theory and, by the same token, gives Aristotle the most important insight into his own theory. The one thing Plato knew about knowledge is that it must be connected to objects which don't change. But these objects (the Forms) are at the same time the cause of objects which do change. Plato has left us with two worlds (the world of Being which doesn't change and the world of becoming which does) but has not explained how they relate. Plato's image of the divided line is very clear that the world of becoming is less real than the world of Being and that the cause of the becoming is the Being. That must mean that the change in the world of becoming can be explained by the world of being. How this is done remains a mystery in Plato's theory.
To explain this we need to understand the nature of causality in greater detail. This is Aristotle's contribution to metaphysics. While it is true that forms are a cause of physical objects, they are not the cause. In fact, says Aristotle there are four distinct causes of objects which can be understood as answers to questions we may have about the nature of any object.
1. What is the object? This question can be answered by the formal cause (the form).
2. How was the object made? This question requires a different answer. What we are after here is the actual agent of change itself, and this, Aristotle refers to as the efficient cause.
3. What is the object made of? This refers to the "stuff" that the object is composed of; the material cause.
4. What is the object's purpose? For the Greeks, things existed for a reason and this was an important component of understanding the cause of any object; this is the final cause.
These four causes arise out of two fundamental principles that all objects are composed of matter and form. These two principles are inseparable. In the natural world, there cannot be matter without form and there cannot be form without matter. This is the theory of hylomorphic composition. Hylomorphic is the Greek word for matter and form and reminds us that in the natural world they are inseparable. Notice I said in the natural world which implies that there is an exception to this rule, which we will come back to in a moment.
One of the benefits of this new theory of metaphysics is that it explains the change. While form explains what an object is, or in Aristotle's words, it is the principle of actuality, matter explains what an object can become. Matter is the principle of potentiality and provides the key for understanding change. Given that each object contains both principles we can understand both what an object is and what it might change to become.
Perhaps an example will help illustrate what Aristotle had in mind. Consider an acorn. We know what it is by its form (the form of an acorn) but we also know what it has the potential to become: an oak tree. The potential is contained in the matter of the acorn (as opposed to the form). Now, we have an interesting question. Is this a complete explanation of the cause of the oak tree? Not since we need to explain the cause of the acorn and this must be another oak tree. Before you accuse Aristotle of going around in circles, remember that the cause of the acorn cannot be the oak tree that comes from it! It has to be a prior oak tree, which means we're not going in a circle, rather backward, in a straight line. Which raises another question: How far back does this series go?
The causal series we have considered here cannot go on forever. If it did we would never observe the final event in the series. In our example, the final oak tree, the one we're looking at now. Another way of thinking about this is as follows. A causal series cannot be infinite because you cannot go through an infinite series. For example, if I said "don't come back to class until you read an infinite number of books" will you ever come back to class? No! You can't complete an infinite reading assignment just as you cannot pass through an infinite causal series. So the causal series must be finite. There must be a first cause. The question is what is this first cause like? We have three possibilities. 1. a combination of matter and form. 2. Pure matter. 3. Pure form. Now, the first two possibilities cannot be correct because they contain potential which must arise from something before it. But if there is anything prior, then it's not the first. So Aristotle deduced that the first cause must be pure form without any matter. Remember the exception mentioned earlier to the theory of hylomorphic composition? This is it. Aristotle called this the unmoved mover. Centuries later, St. Thomas Aquinas would reinterpret this into the familiar form we know it by today: God.
Let’s consider some final interesting implications of Aristotle's theory. As we've seen he does not entirely reject Plato's concept of the form though Aristotle's version is much different. One of the clearest differences is how many forms there are. For Plato, there was one form that gave rise to many objects. No matter how many human beings there are there is only one Form of Human Being. On the other hand, for Aristotle, the form is in the object itself which means that there are as many forms as there are objects. It also implies that the way we gain knowledge of the form is much different. For Plato, Forms were intelligible and so we had to gain knowledge of them through reason. Our knowledge was innate which is why Plato was considered a rationalist. However, under Aristotle's theory forms can be observed through the senses. The mind at birth is like a blank tablet (tabula rasa) upon which sense experience writes knowledge. It was Aristotle who invented this metaphor and, given his denial of innate knowledge, is what makes him an empiricist. It was also Aristotle who claims to have invented logic. It might be more accurate to say that he systematized the ideas into the science we know today. We will now proceed to look at the basic principles of logic.
1. The third man problem
2. The problem of separation
3. The problem of accounting for change
1. To begin with, let's consider the claims made by Plato and see how Aristotle deals with them. Plato's theory claims to account for similarities among groups of objects. The Form explains our ability to see that different human beings (for example) are really examples of the same idea (the Form Human Being). Aristotle, however, disagrees. The only explanation Plato seems to give of the Form explaining similarity is that if you have two people (let's call them James and Jennifer) the Form Human Being will explain what it is that is similar about them.
Does the Form really do this? Aristotle says no and here's why. Suppose I pointed to James and Jennifer and asked whether you think they are similar. You may say yes (or you may say no) but you will probably want me to clarify what makes them similar. To do this, suppose I point to Paul and say that he explains what is similar about James and Jennifer. Have I really answered the question of similarity? It seems that I haven't. What I've done is raise another similarity that needs explaining, in this case, the similarity between the pair James and Jennifer, and Paul. In other words, all I have done is offer a third man to explain the original similarity. The problem is that the explanation doesn't do what it claims to do; it just adds more that needs explaining. This could go on forever! I could point to Shelly to explain the similarity between James/Jennifer and Paul but that wouldn't help either. This is the third man problem.
2. Again let's consider a claim Plato makes about the Forms. They are the cause of objects and our knowledge of them. OK, how does causality usually work? One thing causes another to happen but for this to occur the first thing must be in contact with the second. For example, if I say I am going to cause the lights to go out in the room, I need to turn off the light switch (or cut the power or something). In any case, I have to make contact with something to generate the effect of the lights going out. If I just stand there and say that I am going to cause the lights to go out, nothing happens. There must be contact between cause and effect.
But according to Plato the Forms and objects are NEVER in contact. Remember, the Forms are transcendent, so they are separate from the world of objects. So how could they be the cause of objects? Aristotle says that they couldn't. Unless... Here's where it’s important to remember that Aristotle does not completely dismiss the idea of form. He agrees with Plato that forms are a cause of objects. But Aristotle maintains that forms cannot be the cause if they are separate from the objects. Conclusion: Forms are not separate from the objects. Instead of postulating that the forms are transcendent, Aristotle says that they are imminent; that is they are in the objects themselves. Just as well, we have a hard enough time explaining things in this world without having to worry about a transcendent world of Forms! This insight, that Forms are in the object, has some important implications that we will come to in a moment.
3. The problem of accounting for change may be the most damaging to Plato's theory and, by the same token, gives Aristotle the most important insight into his own theory. The one thing Plato knew about knowledge is that it must be connected to objects which don't change. But these objects (the Forms) are at the same time the cause of objects which do change. Plato has left us with two worlds (the world of Being which doesn't change and the world of becoming which does) but has not explained how they relate. Plato's image of the divided line is very clear that the world of becoming is less real than the world of Being and that the cause of the becoming is the Being. That must mean that the change in the world of becoming can be explained by the world of being. How this is done remains a mystery in Plato's theory.
To explain this we need to understand the nature of causality in greater detail. This is Aristotle's contribution to metaphysics. While it is true that forms are a cause of physical objects, they are not the cause. In fact, says Aristotle there are four distinct causes of objects which can be understood as answers to questions we may have about the nature of any object.
1. What is the object? This question can be answered by the formal cause (the form).
2. How was the object made? This question requires a different answer. What we are after here is the actual agent of change itself, and this, Aristotle refers to as the efficient cause.
3. What is the object made of? This refers to the "stuff" that the object is composed of; the material cause.
4. What is the object's purpose? For the Greeks, things existed for a reason and this was an important component of understanding the cause of any object; this is the final cause.
These four causes arise out of two fundamental principles that all objects are composed of matter and form. These two principles are inseparable. In the natural world, there cannot be matter without form and there cannot be form without matter. This is the theory of hylomorphic composition. Hylomorphic is the Greek word for matter and form and reminds us that in the natural world they are inseparable. Notice I said in the natural world which implies that there is an exception to this rule, which we will come back to in a moment.
One of the benefits of this new theory of metaphysics is that it explains the change. While form explains what an object is, or in Aristotle's words, it is the principle of actuality, matter explains what an object can become. Matter is the principle of potentiality and provides the key for understanding change. Given that each object contains both principles we can understand both what an object is and what it might change to become.
Perhaps an example will help illustrate what Aristotle had in mind. Consider an acorn. We know what it is by its form (the form of an acorn) but we also know what it has the potential to become: an oak tree. The potential is contained in the matter of the acorn (as opposed to the form). Now, we have an interesting question. Is this a complete explanation of the cause of the oak tree? Not since we need to explain the cause of the acorn and this must be another oak tree. Before you accuse Aristotle of going around in circles, remember that the cause of the acorn cannot be the oak tree that comes from it! It has to be a prior oak tree, which means we're not going in a circle, rather backward, in a straight line. Which raises another question: How far back does this series go?
The causal series we have considered here cannot go on forever. If it did we would never observe the final event in the series. In our example, the final oak tree, the one we're looking at now. Another way of thinking about this is as follows. A causal series cannot be infinite because you cannot go through an infinite series. For example, if I said "don't come back to class until you read an infinite number of books" will you ever come back to class? No! You can't complete an infinite reading assignment just as you cannot pass through an infinite causal series. So the causal series must be finite. There must be a first cause. The question is what is this first cause like? We have three possibilities. 1. a combination of matter and form. 2. Pure matter. 3. Pure form. Now, the first two possibilities cannot be correct because they contain potential which must arise from something before it. But if there is anything prior, then it's not the first. So Aristotle deduced that the first cause must be pure form without any matter. Remember the exception mentioned earlier to the theory of hylomorphic composition? This is it. Aristotle called this the unmoved mover. Centuries later, St. Thomas Aquinas would reinterpret this into the familiar form we know it by today: God.
Let’s consider some final interesting implications of Aristotle's theory. As we've seen he does not entirely reject Plato's concept of the form though Aristotle's version is much different. One of the clearest differences is how many forms there are. For Plato, there was one form that gave rise to many objects. No matter how many human beings there are there is only one Form of Human Being. On the other hand, for Aristotle, the form is in the object itself which means that there are as many forms as there are objects. It also implies that the way we gain knowledge of the form is much different. For Plato, Forms were intelligible and so we had to gain knowledge of them through reason. Our knowledge was innate which is why Plato was considered a rationalist. However, under Aristotle's theory forms can be observed through the senses. The mind at birth is like a blank tablet (tabula rasa) upon which sense experience writes knowledge. It was Aristotle who invented this metaphor and, given his denial of innate knowledge, is what makes him an empiricist. It was also Aristotle who claims to have invented logic. It might be more accurate to say that he systematized the ideas into the science we know today. We will now proceed to look at the basic principles of logic.