David Hume’s concept of the self does not only differ from but runs counter to Descartes’s and the other philosophers of the self, such as Plato and Aristotle. This is because, for Hume, there is no such thing as a “self”.
Let me briefly explain why for Hume the concept of the self is an illusion.
First, we need to clarify the term “soul” that Plato and Aristotle used and “mind” that Descartes used.
For Plato, Aristotle, Descartes, and other philosophers who engaged this issue, the term soul or mind refers to a thing or substance which is supposed to be invariably the same through time. So, these philosophers understood the soul as a substance. And as we may already know, a substance is understood in traditional metaphysics as anything, material or immaterial, whose existence is independent on anything else.
So, for these thinkers, the soul or mind is the seat for all our mental states, such as thinking, analyzing, imagining, and the like. This means that the “I”, that is, “the self” is the same all throughout one’s lifetime. One may change physically or emotionally, but the “I” or “self” remains the same.
Now, for Hume, if we possess this substance, then we must have an “impression” of it. However, for Hume, we do not, and cannot, have an impression of such idea. For Hume, therefore, the term soul, mind, or self is one of those meaningless words that we utter.
So, for Hume, Plato, Aristotle, Descartes, and the rest of the philosophers of the self were arguing only about “words” simply because neither of them knows exactly what a soul, mind, or self is. They don’t experience it concretely in the first place, according to Hume.
But how did Hume arrive at the idea that there is no such thing as the idea of the “self”?
Let us now turn to Hume’s theory of ideas.
First, we have to remember that Hume neither affirms nor denies the idea of the self. It’s just that for Hume, talking about it simply doesn’t make sense.
The reason behind Hume’s claim that there is no such thing as the idea of the self can be gleaned from his theory of ideas. So, on Hume’s theory of ideas.
As John Locke argues, ideas come from sensation and reflection. Hume calls it impression. Hence, it must be noted that when Hume used the term “impression”, he means “idea”. When we say “impression” in Hume, this includes both sensation and reflection in Locke. And for Hume, we can have an idea, that is, an impression, of something if we experience it concretely. For this reason, Hume argues that ideas that do not represent something in reality is an abstract idea and, therefore, meaningless. The idea of a “unicorn” is an example of an abstract idea because in the first place, there is no unicorn in reality.
For Hume, there is a multiplicity of ideas; yet all these ideas are linked together that form a coherent whole. According to Hume, this is made possible by the “laws of association”.
According to Hume, there are three laws of association, namely:
1) resemblance,
2) contiguity in time or place, and
3) cause and effect
Hume says that in the law of resemblance, the idea of one object tends to call to mind ideas of resembling objects. For instance, the idea of “honey” resembles the ideas of “sweet” and “liquid”.
In the law of contiguity in time and place, Hume says that when we think, for instance, of “Osama Bin Laden”, we tend to think of “terrorism” or “suicide bombing”.
In the law of cause and effect, Hume says that when we think of, for instance, the idea of a “fresh egg falling to the ground”, it calls to mind the idea of a “splattered mess”.
Please note that Hume puts more emphasis on the third law of cause and effect. As a matter of fact, the law of cause and effect is one of the most important concepts in Hume’s theory of ideas. This explains why after talking about the law of cause and effect, Hume proceeds to the discussion on “perception” and “reasoning”.
On Perception and Reasoning
According to Hume, human understanding is furnished with the faculty of perception and the faculty of reason.
On the one hand, the object of perception are impressions or ideas. And, on the other hand, the object of reason are propositions.
According to Hume, propositions are either
1) a priori statements about relations of ideas or
2) empirical statements about matters of fact and real existence.
For Hume, relations of ideas can be known intuitively or demonstratively. For example, the proposition “All triangles have three angles” is an example of a proposition that can be known intuitively. The proposition “The sum total of all three angles in a right triangle is equal to 180 degrees” is an example of a proposition that can be known demonstratively.
It is important to note that in relations of ideas, the truth can be established without empirical evidence. In fact, in both examples above, we don’t need to resort to experience before we can truly say that all triangles have three angles or, indeed, the sum total of all three angles in a right triangle is equal to 180 degrees. Through mental processes alone, we can truly say that indeed the propositions above are absolutely true.
Matters of fact, for Hume, are propositions whose truth can be discovered through experience alone. Take, for example, the proposition “Sugar is sweet”. Obviously, one cannot really say that indeed sugar is sweet if one has not tasted it. Hence, we can never come to know that sugar is sweet without resorting to experience.
It must be noted that it is “matters of fact” that concerns Hume. In fact, Hume’s theory of knowledge centers on the idea of “matters of fact”.
Hume asks: “What is the nature of the empirical evidence which assures us of any real existence of matters of fact?”
According to Hume, we are assured of some facts by the present testimony of our senses or by the records of our memory. In other words, for Hume, we know that facts exist in reality simply because we experience them. This explains why Hume was an empiricist.
But the question is by what means do we get beyond such facts? In other words, how can we be sure that such facts exist in reality? This is the central question in Hume’s theory of knowledge, which he developed in his famous work Enquiry Concerning Human Understanding.
So, again, by what means do we get beyond such facts?
According to Hume, it is by means of the relation of cause and effect that we are enabled to make, more or less reasonable, predictions and conjectures that go beyond the data of perception and memory.
But how do we arrive at the knowledge of cause and effect?
The answer, for Hume, is not reasoning a priori (as the rationalists would have us believe) but entirely from experience. Again, for Hume, our knowledge of cause and effect relation remains limited to experience. Of course, the mind steps beyond experience and engage in reasoning. But for Hume, this kind of reasoning is not supported by any argument or process of understanding through relations of ideas or through reasoning a priori. This kind of reasoning, for Hume, is supported by habit or custom.
Now, it must be noted that for the rationalists, cause and effect relation falls under a priori reasoning. In other words, for the rationalists, there is a necessary connection between cause and effect. For example, if it is raining at the moment, then reason tells us that the road must be wet. However, for Hume, in reality there is no necessary connection between two events, between cause and effect. The idea of a necessary connection is produced in the mind not through reason a priori, but through habit or custom. Hence, Hume did not reject the idea of “connection” wholesale. He only rejects the idea of connection employed in metaphysical reasoning, that is, the a priori reasoning in rationalism.
Again, for Hume, there is (necessary) connection only through experience (in common life and practice) which is based on habit. Hence, the only evidence assuring us of any real existence and matters of fact is experience, that is, 1) the present testimony of our senses, 2) the records of our memory, and 3) the causal (experiential) reasoning based on the empirically observed regularities of past experience.
Now, let’s go back to Hume’s concept of the self and apply what we have learned from his theory of ideas.
For Hume, if we look inside ourselves, we cannot find an impression (that is, an idea) of a “self” as a substance. In other words, we cannot experience the self concretely. Hence, for Hume, we have no reason to suppose that we are “selves” or “mind”, or “souls”. As Hume famously says, we are just a bunch of impressions.
This means that like the idea of an ultimate or necessary cause (as we discussed above) the idea of “self” is natural and inevitable. We are inclined to think about the self because we exist, because we are accustomed to it. However, for Hume, like the idea of an ultimate or necessary cause, the idea of a “self” is a mere fiction. Again, the idea of the self is anything but a bundle of impressions or, in other words, the idea of the self is just a supposition.
Indeed, for Hume, the idea of the self is simply an idea and there is no guarantee that it exists in reality. Again, it is natural to talk about it because we exist, because we are accustomed to it, but to suppose that there is within us an unchanging substance called the “self” is an illusion, at least for Hume.