January 21, 2019

## Causal vs. Descriptive Claims

### Two varieties of empirical claims:

descriptive claims: claims about what exists (or has existed/will exist) in the world:

causal claims: are claims about the how one phenomena ($$X$$) affects or causes another phenomena ($$Y$$). Causal claims state that $$X$$ acts on $$Y$$ in some way, not merely that they appear together in some pattern:

## Descriptive Claims

claims about what exists (or has existed/will exist) in the world:

• what phenomena exist (what kinds of things exist?)
• what is the type of a specific phenomenon (what is this thing?)
• amount/frequency of phenomena (how much of something is there?)
• relative amount/frequency of phenomena across different places/times (how much of something is there here vs. there/now vs. then?)
• what patterns are there in the shared appearance/non-appearance of different phenomena (does this thing usually appear together with that other thing?) do not conflate with causal claims

## Causal Claims

• the effect that one thing or event has on another thing (effects of causes)
• the cause of some event or thing in the world (causes of effects)
• the conditions under which some thing or event happens (causes of effects)
• the process through which one thing affects another (causes of effects)

## Causal Claims

"The chance of cancer increases with age"

Same as:

"The chance of cancer increases as age increases"

## Causal Claims and Prescriptive Claims

You and your friend win a sum of money in a lottery

You and your friend agree:

the most important ethical goal is minimizing human suffering. (value judgment)

### You disagree on what to do:

1. We should donate mosquito nets to stop malaria (prescriptive claim)

2. We should give money directly to impoverished people (prescriptive claim)

## Causal Claims and Prescriptive Claims

• Assuming less malaria is good, resources are finite
• What if mosquite nets don't prevent malaria, or cause more harm (tangling deaths)?
• Showing "Malaria nets does not reduce malaria" is informative!

#### Accepting a prescriptive claim requires both a value judgment and accepting a causal claim

bonus term: instrumental rationality

## Falsifiability

### an empirical claim is falsifiable…

if that claim can be shown to be wrong by a specific empirical test. Even if we never do show the claim is wrong, it is falsifiable if, in principle it could be shown to be wrong.

• e.g. The Earth orbits the Sun

### an empirical claim is unfalsifiable…

if there is no empirical test that can be done to show the claim is wrong

## Falsifiability

### Because science considers alternatives/is open to being wrong…

we can only scientifically evaluate claims that can, in principle be shown to be wrong.

The best claims/theories are those that stand up to many tests to show them wrong.

No claims/theories are "proven", they have "not yet been proven wrong"

• invitation to challenge

## Falsification

### Contrast with verification

If we had an empirical claim, $$H_1$$ ($$H$$ for hypothesis)

and, if $$H_1$$ were true or valid, then it implies we should make certain empirical observations $$O_1$$

Verification says that

1. $$H_1 \rightarrow O_1$$

2. We see $$O_1$$

3. Therefore, $$H_1$$ is valid

## Falsification

Many people reject verification because many different, incompatible claims are might imply the same observed evidence

1. $$(H_1, H_2, \ldots, H_k) \rightarrow O_1$$

2. If we observe $$O_1$$

3. $$H_1$$ is not proven

## Falsification

If a claim $$H_1$$ is falsfiable, there must be observable implication $$O_1$$ that, if it were untrue, would invalidate $$H_1$$. So, the logic of falsification is:

1. $$H_1 \rightarrow O_1$$
2. $$not\ O_1$$
3. Therefore, $$not\ H_1$$

## Examples

$$H_1:$$ "Immigrants are coming across the border to kill you" ~ Donald Trump

Verification

1. $$H_1 \rightarrow$$ Murder committed by an "illegal immigrant"

2. There has been a murder by an "illegal immigrant" see here

3. Therefore, "Immigrants are coming across the border to kill you"

## Examples

$$H_1:$$ "Immigrants are coming across the border to kill you" ~ Donald Trump $$H_2:$$ "One immigrant committed murder" $$H_3:$$ "Two immigrants committed murder" $$H_4:$$ "Immigrants are less prone to murder than native born citizens"

Verification?

1. $$(H_1, H_2, H_3, H_4 \dots H_k) \rightarrow$$ Murder committed by an "illegal immigrant"

2. There has been a murder by an "illegal immigrant" see here

3. Therefore, $$H_1, H_2, H_3, or\ H_4$$ could be valid

## Examples

$$H1:$$ "An invisible and undetectable Flying Spaghetti Monster created the universe "after drinking heavily". According to these beliefs, the Monster's intoxication was the cause for a flawed Earth. Furthermore, according to Pastafarianism, all evidence for evolution was planted by the Flying Spaghetti Monster in an effort to test the faith of Pastafarians."

Falsification?

1. $$H_1 \rightarrow ?$$

2. $$?$$

3. $$?$$

What observable implication of this could be proven wrong?

## Examples

$$H_1:$$ "According to Pastafarian beliefs, pirates are absolute divine beings and the original Pastafarians. Global warming, earthquakes, hurricanes, and other natural disasters are a direct effect of the shrinking numbers of pirates since the 1800s."

Falsification

1. $$H_1 \rightarrow$$ Increase in Pirates would decrease Global Warming

2. $$not$$ Increase in Pirates produce decrease in Global Warming

3. $$not \ H_1$$

In principle, this is could be falsified. (What kind of claims is $$H_1$$?)

## Examples

$$H_1:$$ "Human beings are rational actors who maximize their utility."

1. $$H_1 \rightarrow$$ People make decisions that maximize their expected monetary earnings.

2. In games, people choose to take monetary losses to punish people who violate expected social norms ($$not \ O_1$$)

3. $$not \ H_1$$?

4. Frequently, scholars say: utility functions also place value on adherence to social norms (preferences over process, not outcome)

• Rational choice theories may not be falsifiable