Connection of Ideas

In book three Hume talks a good deal about the connection that exists between all ideas. Hume talks about three principles by which ideas may be connected. The first principle he talks about is resemblance, this is where we see a picture of a tree and we then think about the tree. The second principle he talks about is contiguity of time and place, this is where if we are to mention one apartment we then get to discussing others. The last principle he talks about is cause and effect, where when we think of a cut or scrape and then we think about the pain that followed it. Hume then goes on to say that he has no reason to not put out more prinicples for the connection of ideas, expect for the fact that he can not come up with anymore. Though he does then say that even though he can't think of anymore no more are needed. For example, association by means of contrast or contrariety can be seen as a combination of resemblance and causation.

Imagination

In the second book Hume talks about imagination and how the human mind is an unlimited organ. Hume states that our imagination is merely the compounding of ideas. Hume comes up with two points to explain this idea. First he says that all complex ideas are merely compounded out of simple ideas and these simple ideas come from simple impressions (everyday things like human form and intelligence). Hume uses the example of God being a supremely good and intelligent being. We have the idea of goodness and intelligent and allowing them to have no limit allows us to imagine the being of God. Second Hume talks about how our imagination is limited to the impressions we are able to take in. So for example a person that is blind is not able to imagine color and a person that is deaf could not imagine sound.

Origin of Ideas

According to Hume thier is a distinction between impressions and ideas. Hume says that ideas are the weaker form of impressions. They are lacking something that impressions have, they are less vivacious. Impressions according to Hume are sensations and ideas are memories and ideas. Hume gives the example of a person eating an orange. The impressions of eating the orange, taste, feel and smell are stronger then some one imagining eating an orange. Hume then goes on to say that both the color red and anger are considerend impressions (everything we hear, see, touch, smell, feel and love) and ideas arise when we reflect back on those impressions.

Easy & Obvious Philosophy vs. Accurate & Abstract Philosophy

Hume begins the "Enquiry" by saying that there are two kinds of philosophical thinking. The first is "easy and obvious philosophy" and the second is "accurate and abstract philosophy". He describes the first as being written in a poetic style and that it uses examples from everyday life so we can see the difference between right and wrong.He says that this type of philosophy is popular and follows from common sense, therefore there are rarely errors in it.

The second philosophy, accurate and abstract philosophy, does not direct our behavior. Instead, it focuses on what causes that behavior and why we do the things we do and uses abstract reasoning to attempt to make sense of it. He says that since this area of philosophy does not use common sense, errors are made often and because of this, this area is sometimes rejected.

Hume goes on to say that the best objection against A&A philosophy is that it is a confused attempt to explain what we don't know by blind prejudice. Hume's reply to this is that this should be more reason for us to study it closely.

Hume on Causality Part III: Implications for Science

Given the considerations in my last two posts, we can ask questions of major consequence. The first is: what, then, given a new understanding of how we make inferences concerning causality, are the implications for science? What kind of certainty can we really furnish? Can we really say that we know that one event will follow another simply because it always has in the past? An this brings us back to one of Hume's initial questions: What reason (if we say that we indeed do know that one event will follow another because of past experiences) do we have for believing that the future will be like the past? It does not seem like we have any real reasons other than our deeply-implanted beliefs which are a result of custom and habit.

Here is the big question for science: What is a law?
A law is supposed to be a rule that dictates how nature behaves. A law is supposed to give us certainty in knowing how one body willact in a given situation. But given Hume's considerations, it seems like a law is more like a description of our past experience. Saying that something is a law of nature might be similar to saying "Well, physical bodies have behaved in such and such manner in the past without fail, so much so that we conclude that they will always behave in this way". Here is the killer for realists about scientific laws: Are the words "law" and "causality" really just useful fictions for describing our experience of the world? Maybe these words do not refer to anything that really exists out there in the physical world- maybe they are just useful terms to help us express what we are trying to say when it comes to explaining scientific theories.

Hume on Causality Pt. II: The Problem of Induction

Given the considerations in my last post, it seems evident that there must be something wrong with how we make inferences concerning cause and effect. If what we call 'cause' is really just "an object, followed by another, and where all the objects, similar to the first, are followed by objects similar to the second"(Hume, VII pt. II), then it seems that our idea of causality is not one produced by knowledge, but actually by habit or custom. What we really mean, then, when we say that something causes something else, is that in the past, it has always been the case that one event follows another. We do not actually have knowledge of what it is in the one event/object that "causes" the other event or object to happen. That is, we are ignorant of the force or power which compels one event to follow another. Our reasoning, if any, proceeds in this manner of induction:

Premise 1. At time q event A was accompanied by event B.
Premise 2. At time r event A was accompanied by event B.
Premise 3. At time s event A was accompanied by event B
Premise 4. At time t event A was accompanied by event B.

CONCLUSION: Event A causes event B.

Hume points out that we would never infer the conclusion after only one instance of the above happening. If we only observed it once, we would say only that events A and B were conjoined in our experience. But because we experience a constant conjunction of event A and B, we infer that there is some type of connection between them, which we call causality. We do not see this connection, nor do we know what it is.

Hume on Causality

Hume is concerned with the inferences we make concerning what we call "cause" and "effect". He asks what the basis is for one to see one event follow another and then to conclude that the first event caused the second. First of all, this inference is not made on the basis of a priori reasoning, that is, reasoning which precedes experience. Rather, the inference is based on what we experience. What reason do we have, Hume asks, for concluding that since one event was followed by another in the past, that this conjuction will hold for the future. Take bread, for example. Hume asks what justification we have for believing that since bread has nourished us in the past, that objects similar to the bread we have eaten in the past will also nourish us. In other words, what reason do we have for believing that the future will be like the past? But we almost never conclude that there is a causal relation between two events until we have experienced them cnjoined in many instances. For example, fire has never in the past failed to be accompanied by heat, nor snow by cold, so we naturally make the inference that fire causes heat and snow causes coldness. Since we have not discovered WHY the one event follows the other, but that we continue to make the inference that the two events are causally related anyway, Hume concludes that it is not because of any reasoning that we make the inference, but because of habit/custom.