Constant Conjunction and the Problem of Induction

Transcription

1 Constant Conjunction and the Problem of Induction You may recall that Hume s general empiricist epistemological project is to explain how we obtain all of our knowledge based fundamentally on the idea that all of our knowledge comes from sensation and reflection. The ultimate source of all our ideas, and consequently all our knowledge, is the basic data we get from our senses. And we are able to generate new ideas by reflecting on, or thinking about the ideas we obtain from experience. We have also seen that whether the objects of our experience actually correspond to objects outside of our experience, i.e. objects that exist in the external world, is not knowable. This is basis of the main criticism of the correspondence theory of truth. There are significant limitations on what genuine knowledge can be obtained from the senses. What is the difference between what I am calling an object of our experience and an externally existing object? Given these limitations, it is interesting to consider what we really know about causal relations. When we consider the case of two colliding billiard balls, we consider the incoming ball to cause the ball that it strikes to move. When we make this judgment, we are thinking of an interaction between two material objects. These objects themselves, however, are outside of our experience they are in the external world.

2 This entails, then, that our notion of a causal connection between a cause and an effect does not come from experience. It is something that we add to events involving the objects of our experience. How, then, do we understand the nature of causal relations? Consider what it is that we actually experience. We experience a wide variety of pictures, sounds, smells, tastes and feelings. From this information we form ideas of objects that exist outside of us and we associate a variety of properties to these objects. For instance, consider a mint. From our various experiences with mints, we associate a white colour (generally), a particular taste and smell and a feeling of hardness. We also associate with a particular mint a particular size, shape and weight. As a slight aside, consider these different properties. Which ones do we suppose to be actual properties of the mint? We come to form strong beliefs about the nature of the various objects of experience. This enables us to navigate the world to understand the way that things (tend to) work and how we should interact with the various things that we experience. As we have seen, however, (most of) these beliefs about the external objects corresponding to the objects of experience, including beliefs about how they interact causally, cannot constitute genuine knowledge.

3 What is going on here then? Consider the following analogy. When we watch a movie it appears that there are objects moving around and people communicating with each other and so on. We also hear sounds that correspond to things that are happening on the screen. All this gives the impression that we are watching a continuous sequence of events happening. As we all know, however, what we are actually seeing is a sequence of still images flashing at a rate of 24 per second. And we are hearing an audio track synchronized to particular frames of the film. Our experience of the world works in much the same way. All we actually see is a sequence of images and sounds, smells, tastes and feelings that we associate to certain objects of our experience. The concert of all this information from the senses gives us the impression that there are actual objects existing in space and time that we interact with. Where, then, does our notion of cause come from? The names cause and effect refer to two objects or events that are located in the same place and occur right after one another in time. In Hume s language, the two objects or events are spatiotemporally contiguous. We come to identify one object or event as the cause and another as the effect when we observe over and over the spatiotemporal contiguity of the two objects or events.

4 In the case of the billiard balls, we always see an impression of one advancing followed by an impression of the other retreating. We call the advancing ball the cause of what we call the effect, the retreating ball the advancing ball causes the retreating ball to move off. In other words, we apply the words cause and effect to two objects or events that are constantly conjoined. Hume then points out that this is all there is to causation. We never have any experience of a necessary connection between the two events. If there is such a necessary connection, then it is a property of the externally existing objects that we have no direct experience of. It is quite obviously the case that there is a great degree of regularity to our experience of causes and effects. Indeed, this is what makes science possible. All of the causal laws that we derive from experience, however, are only based on the constant conjunction of particular kinds of events. Consider the case of mixing baking soda and vinegar together. Whenever we mix the two substances, we hear a fizzing sound, see the formation of bubbles, smell a particular odour and we see that a gas is given off. We then say that the act of mixing (or a chemical reaction between) the two substances is the cause of what we observe afterward.

5 The main part of the chemical explanation of this phenomenon is that sodium bicarbonate (NaHCO 3 ) reacts with acetic acid (CH 3 COOH) to cause the production of, among other things, carbon dioxide (CO 2 ). The carbon dioxide is responsible for the gas, bubbling and part of the smell. What sorts of things are added here that go beyond what we really know about the cause-effect relationship? You might then ask why it is that we often feel that there is a necessary connection between two events. Hume s answer here is that it occurs as a result of a custom or habit that we develop of thinking of the effect whenever we think of, or see, the cause. More strongly than that, we believe that we will experience the effect whenever we experience the cause. What implications do Hume s conclusions have concerning the prediction of future events? Let s return to the film analogy for a moment. Since all we actually experience is a rapid sequence of still images, the motion of objects is an illusion. But, since any image could follow any given image, the regularities among the objects that appear could change at any moment. Our experience works in much the same way. Since we have no experience of actual externally existing objects that are subject to specific causal laws, any cause effect relationship could fail to hold in the future.

6 This exposes significant limitations to our actual scientific knowledge. According to Hume, any given physical law could fail to hold in the future. For instance, for all we know, the force of gravity could suddenly become repulsive instead of attractive in the future, since we cannot know that it is necessary that the gravitational force between massive objects is attractive. What consequences do Hume s skeptical remarks about induction have for, for instance, the chemical explanation of the reaction between baking soda and vinegar?

7 some things to be aware of with respect to paper writing The use/mention distinction Socrates is human Socrates has 8 letters Where do we need to add quotes to the following to make it make sense? According to W. Quine, Whose views on quotation are fine, Boston names Boston, And Boston names Boston, But 9 doesn t designate 9 Make sure that you state your thesis at the end of your introduction, just after you lay out the plan of how you propose to argue for your thesis. An argument is a sequence of statements (the premises) that establish or support another statement (the conclusion). A theory, among other things, is something that can give explanations and understanding of a wide variety of things. Examples are Newton s theory of universal gravitation and the correspondence theory of truth. Theories are general they can be used to generate many arguments.

8 It is not acceptable to use text message abbreviations in academic papers. Where the symbol appears, a new paragraph should start. Whenever you move on to a new main point, you start a new paragraph. Make sure that you reference quotes or the paraphrasing of someone else s words. Make sure that you use a consistent system of citation, and make sure that you provide enough bibliographic information at the end of your paper so that I could locate the source if I wanted to. You lose marks when this is not done properly. Be careful when using websites as resources since the information that you find is often wrong or inaccurate. Be careful with semicolon use. Take a look at the following document: When you make an addition to a quote for clarity, use square brackets [ and ]. When I have a dash and then a comment, I am usually referring to the sentence that the dash points to. A vertical curved line usually means that I am referring to several sentences or a paragraph.

9 Marking Scheme for this essay: Exposition/3 Quality of Arg./4.5 Clarity/1.5 Org.+Style/1