David Hume's Association of Ideas
It can readily be noted that in most instances our thoughts flow smoothly from one to another with some degree of coherence. That is, our thoughts and ideas are not merely random and nonsensical, but that there is some unifying connection between ideas that allows us to proceed in thought from one idea to another that appears to us sensible and orderly. However, I intend to argue that not all thoughts or ideas are connected by a principle (or principles), as Hume argues they are.
To begin, Hume argues that all ideas are connected by at least one of the following three principles: 1) resemblance; 2) contiguity in time and place; and 3) cause and effect. Resemblance can be thought of as a principle to trigger ideas that resemble something previously experienced. For instance, when viewing a picture of a man who resembles one’s father, one might be led to have thoughts about one’s father. Therefore, it was the resemblance of the man in the picture to your father that led you to think about your father, thus resemblance has been a connecting principle for your flow of ideas in this case (i.e., from the passing of one idea to the next idea).
Similarly, contiguity in time or place is a connecting principle of ideas because the thought of a particular object or event might lead one to think of another object or event closely related in either time or place. For example, one might think of a particular lake, which might in turn lead one to think of the cottage located on that lake, and then lead one to remember a weekend spent at that cottage with one’s family, etc. These thoughts are all connected by the principle of contiguity because the objects (lake, cottage, etc) are all geographically approximate to one another, and all occurred in a specific time frame (i.e., one weekend).
Likewise, the principle of cause and effect serves as the final connecting principle of ideas for Hume. When one observes some event, one is often lead to inquire as to the cause of the event. For example, when one hears of the death of a loved-one, one will immediately inquire into the cause of death. The thought of death leads us to thoughts about how deaths are brought about. Therefore, the principle of cause and effect operates as the third and final connecting principle of ideas.
It might be thought by some, that Hume has left open the notion that there may be other principles of connection between ideas that have yet to be discovered. However, Hume does not allow that there may be other principles that could serve as a connecting principle of ideas. He states, “It is sufficient, at present, to have established this conclusion, that the three connecting principles of all ideas are the relations of Resemblance, Contiguity, and Causation” (p. 107). This is where I take issue with Hume’s argument.
I do not necessarily think that there is a fourth principle that Hume has not identified; nonetheless, I disagree with Hume’s conclusion that all ideas are the result of the relations between the three identified principles. I do agree that the three principles Hume has identified as connecting principles of ideas are at work when we have most ideas. However, I think Hume has neglected to consider a second possible conclusion to the connection between ideas, mainly that not all ideas are connected by the three principles. In fact, I believe that some of our thoughts have no continuity or connection whatsoever, and that any attempt at explaining a connection by Hume’s three principles could never be successful. Even Hume may have stated something that supports my argument.
Hume is arguing for his thesis that all ideas are connected by the three principles he has identified. He then goes on to say, “In our more serious thinking or discourse…any particular thought, which breaks in upon the regular tract or chain of ideas, is immediately remarked and rejected” (p. 101). In other words, Hume is saying that when we are in deep thought, we immediately notice when a random thought has entered (i.e., a thought that has no connection with the train of thought you were in), and then we reject it (again, because this random thought has no relevance to what it was we were thinking about). Does this suggest that maybe not all ideas are connected?
Here we have an example of where a random thought does not belong in our chain of thoughts. I would argue that the reason why the intruding thought seems strange is because when we identify the intruding idea and we compare it to our train of thought we can analyze it at that point and say, ‘this intruding idea does not appear to be related by the principles of resemblance, contiguity, or cause and effect; therefore there is either some fourth principle that has yet to be identified as a connecting principle of ideas which explains this intrusion of a random thought’, or, my conclusion, ‘maybe some ideas are not connected by any principles whatsoever.’ In other words, the very reason the intruding idea seems so out of place is because there is absolutely no connection whatsoever between it and the rest of our thoughts.
Hume might have responded to these two conclusions as follows. First, Hume would likely argue that since, upon analysis of his own thoughts, he has found that in all instances, every thought he has ever had has always been connected by the three identified principles of the association of ideas. Therefore, with no remaining examples of unexplained transitions in thought left to explain, why search for a fourth connecting principle? In other words, a fourth principle is not needed, because every transition, from one thought to the next, has been successfully explained by the three principles already identified.
Second, Hume may protest my conclusion by claiming that there may be no examples of anyone ever having experienced any ideas that were not related by resemblance, contiguity, or cause and effect. To this objection I would respond that on many occasions I, myself have experienced many instances where I have passed from one idea to the next without having experienced any of Hume’s three principles. For example, one moment I may be thinking about some philosophical dilemma, the next minute I may wonder what I am going to have for dinner. Can it be said that the philosophical dilemma I was considering resembled, in some way what it was I was going to have for dinner? This does not seem plausible, for there was nothing in the philosophical argument about food, hunger, etc. Or can it be said that the philosophical dilemma is contiguous with what it was I was going to have for supper? It is unclear how this principle could possibly apply to this example. Finally, can it be said that the principle of cause and effect is related to me wondering what it was I was going to have for supper while in the middle of a philosophical dilemma? The answer to this question may be yes, but it is not the type of cause and effect relation that Hume argues for, as we will see.
Perhaps at the time when I was considering the philosophical dilemma, I got the feeling of hunger in my stomach, which caused me to think about what I was going to have for supper. Therefore, the principle of cause and effect did play a role in my thinking of what I was going to have for supper, but the principle of cause and effect has not here, operated in the way Hume had intended. Hume does not mean to explain by the principle of cause and effect how a feeling can result in an idea (i.e., the feeling of hunger producing the idea of what to have for supper); Hume meant that in order for cause and effect to have a role in the connection between ideas, idea A (the cause) must cause an agent to produce idea B (the effect). Clearly this is not the case in this example that the philosophical argument caused me think about what was for supper; it was the feeling of hunger that caused me to wonder what to have for supper. It would appear that in this case, none of the three connecting principles of ideas are able to explain how my thoughts of a philosophical argument are connected to my thoughts of what to have for supper. And we should not think that this case, which fails to be explained by Hume’s three principles, is a minor exception to be ignored, as I will now argue.
Many times before, I have been in a deep train of thought and then, all of a sudden, I start to hum a song in my head. Upon analysis, I can determine whether there are any of Hume’s three connecting principles of ideas present to explain how it is that I am presently humming a song in my head. When none of the three connecting principles are found, I am left to conclude that there must either be some fourth principle at work between the connection of ideas, or simply that sometimes there are no connecting principles at all. And since the transition in thought from a deep train of thought, to the humming of a song is so mysterious and so void of any apparent connection by any principle that I am aware of, I must conclude that sometimes, it may be that there are no connecting principles between some ideas.
Furthermore, there is no reason to think that my mind operates in a different manner than the minds of other people. Thus, it must be the case that other people are able to identify instances where not all ideas are connected through Hume’s three principles of connection.
In conclusion, I agree with Hume, that where there are identifiable principles that serve to connect ideas from one to another, the principles of resemblance, contiguity in time and place, and cause and effect will be present, and therefore explain most of the instances of the connections of thought. However, because I am able to identify thoughts that do not appear to be connected by Hume’s three principles, and furthermore, that my mind operates like everyone else’s, it must be the case that there are many instances where there are no connecting principles between ideas.
David Hume, An Enquiry concerning Human Understanding, ed. Tom L. Beauchamp (Oxford: Oxford University press, 1999).