Dr Magda Osman Room 2.25 Office hours Mondays Causality Dr Magda Osman Room 2.25 Office hours Mondays

Exactly what is a cause? I am absolutely sure what a ‘cause’ is I am not quite sure what a ‘cause’ is I am beginning to wonder whether I know anything at all about what a ‘cause’ is

Learning Objectives Understand Hume’s position on causality Have a good comprehension of the problem of induction and have a good understanding of the Grue Problem Appreciate the Salmon’s approach to causality in context to Hume’s position

Why is causality so important? (I) Without causal assumptions – i.e. the cause effect relations in the world we cannot do the following (Osman, 2010; 2014): Predict the world around us Assert any control around us The problem is, we can’t take these truisms for granted

Why is causality so important? (II) Establishing the truth of causal claims is a very important activity in most sciences. This is because causal claims are thought to advance two central goals of the sciences: Citing causes means to cite explanatory factors Knowing causes provides knowledge of means to bring about desired effects The problem is, on what grounds can we make inductive/causal inferences?

Example – Getting a Cold We feel a cold coming on, SO We buy vitamin C tablets, and aspirin. For the next two days we take vitamin tablets. This doesn’t’ make things better We reason that vitamin C doesn’t work, so we take aspirin tablets. After a few days the aspirin seems to be working. After a week the cold has gone. Salmon, W. (1984). Scientific Explanation and the Causal Structure of the World. Princeton, NJ: Princeton University Press.

Did taking medicine/vitamin C cause the cold to go away? Yes No Unsure

Qs How do we know that our actions have effects on the world? How do we know if there is a causal association between pairs of events that occur close in time and space? These questions have a bearing psychologically, as well as scientifically in the way we understand the world around us

A matter of perspective 1 - cold Person perspective 1. we feel that we can act (i.e. taking vitamin c, or aspirin) in ways that will generate a change in a desirable direction (e.g., getting better) 2. we believe there is a causal link between our actions (causes) and effects that we observe. 3. so, when we decided to take aspirin then we infer that this helped to make ourselves get better. This is a causal/inductive inference Osman, M. (2010). Controlling Uncertainty: Learning and Decision Making in complex worlds. Wiley Blackwell Publishers

A matter of perspective 2 – cold Outside perspective 1. Average rate of recovery from a cold is a week, irrespective of medication 2. This implies that regardless of our actions the cold will be gone in approximately a week

Does knowing that the length of the cold will not be effected by your actions, mean that you will now NOT take medicine when you get a cold next time? Yes No Unsure

So, did the person cause themselves to get better? How can we know for sure that we are the cause of events? – especially since events in the world may merely correspond with our assumptions? Events might just happen to correspond in such a way that it appears that there is causal mechanism - it doesn’t mean that this is a reflection of reality, we just see causality where there is none

Hume BUT - causality is a concept that disguises what are essentially: Belief: If C (cause) then E (effect) so if C happens, E must follow. Hume's terminology: There is a necessary connection between cause and effect A cause has a power to produce its effect Hume’s denied that there is a necessary connections in nature. Events appear to logically (i.e. necessarily not probably) follow one from another, which we assign a causal relation to, BUT - causality is a concept that disguises what are essentially: spatial contiguity – things (event a, event b) happen close in space temporal succession – things (event a, event b) follow one after the other Michotte illusion.

Causality exists in our heads, not the real world Hume means the following The gap between event a that is always followed by event b that we experience and fill by referring to causation, and that we go on to attribute as a matter of fact that event b that follows event a is cause and effect, is a necessary connection, but it only exists in the mind not outside of it. Why? Because all we are perceiving are regularities, not causal connections – the causal connections are a construct of the mind to help make sense of the association – based on habit

But why is causality all in the mind? Hume’s problem – The problem of induction We can’t look to past experiences of c and e, any more than we can rely on our reasoning to say “In the future c will be the cause of e” because: 1. We have to assume that past experiences must resemble those of the future {we can’t know this for sure} 2. We have to assume the past, present and future conditions in which c and e occur must be uniformly the same {which we cannot assume}

There was no interval betwixt the shock and the motion. Hume’s comment: Billiard Balls Michotte illusion. Here is a billiard-ball lying on the table, and another ball moving towards it With rapidity. They strike; and the ball, which was formerly at rest, now acquires a motion… There was no interval betwixt the shock and the motion.

I can discover nothing in this that is causation Hume’s comment: Billiard Balls Contiguity in time and place is therefore a requisite circumstance to the operation of all causes. Priority in time, is therefore another requisite circumstance in every cause. i.e. order Constant conjunction –Every object (like the cause), always produces some object (like the effect). i.e. Pairs of events happen in combination that co-occur I can discover nothing in this that is causation

Hume suggests that causality is all in the mind, how convinced are you by his proposal Entirely convinced Marginally convinced Unsure Marginally unconvinced Entirely unconvinced

Problem of induction Causality is problematic – 1. Causality is a psychological concept, not a concept about a real mechanism. Causality is an illusion Problem of induction then – induction allows us to make predictions about future events based on prior experiences/observations, - this is built on an understanding of causal relations, which cannot be justified induction relies on generalizing from prior experiences/observations to other experiences/observations of the same kind – this is as problematic – for the same reasons as inferring cause – the extension is a mental trick not a reflection of reality.

Problem of induction- revamped The practical way we escape the problem of induction is – habits. 1. Regularities can help to form habits – e.g., this match from the box when struck makes fire, when I strike other matches, they make fire 2. Regularities can help to form descriptions/statements about the world e.g., teapots in my house have white lids, so teapots in other people’s houses will have white lids. Goodman (1955) revamped the problem of induction: How then can we reliably tell the difference between regularities that seem genuine from those that are spurious?

Grue Problem Scientists discovered a substance “Grue” Definition: an object is grue in cases where (i) it has been observed to be green, or (ii) it has not yet been observed and it is blue. 2. Grue objects never change colour. Evidence that all emeralds are green consists of emeralds that have been observed to be green. 4. All those emeralds are also grue. 5. The evidence is equally strong for two hypotheses. a. Green hypothesis: all emeralds are green b. Grue hypothesis: all emeralds are grue. 6. Hypotheses make different predictions. a. Next emerald is green. b. Next emerald is grue (therefore blue). 7. If confirmation is implication in reverse, grue hypothesis—with its prediction—is as well confirmed as the green hypothesis.

Grue problem In science we don’t look for one single hypothesis, Instead, we look for the best hypothesis that fits the evidence So, a scientific statement such as All emeralds are grue Is just as valid as a statement such as All emeralds are green If we don’t have induction to rely on (which we use to make causal associations) infinite statements can be used to describe the same observations

Grue Problem 1. There are an indefinite number of ways in which we can describe the data. 2. There will be different and incompatible ways of extrapolating from the data. i.e., different descriptions entail different generalizations which we can draw, and hence different predictions and explanations which we can infer Hence there is a problem: What is the rational procedure for selecting one description over another?

Can probabilities help? Salmon (1989) example: Say there is a general causal claim: when a person takes vitamin c their cold will be alleviated with a high probability after a week 9 out of 10 times when ever a person gets a cold, they will recover after a week. I get a cold, and have taken vitamin C, and so also expect that my cold will disappear with a high probability after a week. Hempel (1965) proposed that this inductive argument – which forms the basis of an explanation is governed by a statistical generalization. NOT CAUSALITY. The premises are true (e.g., vitamin c, colds) and the conclusion (e.g., one week recovery period) follows with a high probability.

BUT – there is a problem with using probabilities I By focusing on probabilities, we are persuaded by good inductive arguments that are based on high probability occurrences, not low probability events. But, not all rare occurrences are spurious – they need causal explanations For instance - Lethal violence in schools, the Challenger space shuttle disaster, Economic Crises,

The problem with using probabilities II High probability is not always sufficient to be a good statistical explanation –which for inductive purposes we use to make a causal inference For example – Salmon’s (1989) – cold example show how high probability doesn’t necessarily allows us to make a correct inductive causal inference.

Exactly what is a cause? I am absolutely sure what a ‘cause’ is I am not quite sure what a ‘cause’ is I am beginning to wonder whether I know anything at all about what a ‘cause’ is

Conclusions Though a number of philosophers search for a universal theory of causation, many have given up and turned to other issues The reason is that every theory that seeks to define causation (whether reductive or not) can’t solve the problem of induction

Where does our concept of cause come from: is it really all in the mind?