Preview: Ethics vs Physics

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Preview: Ethics vs Physics

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McCloskey et al. (1980, p. figure 2B)

I want to approach this topic indirectly ...

First point: we don’t base our understanding of the physical on common-sense.

‘In putting forward an account of light, the first point I want to draw to your attention is that it is possible for there to be a difference between the sensation that we have of it, that is, the idea that we form of it in our imagination through the intermediary of our eyes, and what it is in the objects that produces the sensation in us, that is, what it is in the flame or in the Sun that we term ‘light’’

(Descartes, 1998, p. ][p. 81 (AT XI:3))

Descartes, The World (AT 3)

This quote is quite complex. Let's try to simplify. (Do this when quoting in your own work.)

Note that this is Descartes’ starting point (in an early work that was never published because of fear of religious repression.)

Further illustration (not from The World). Descartes’ explanation of why the rainbow is a bow. Relevant because of the gap between sensory perception and the things which cause it. And shows Descartes examines sensory perceptions.

sensory perceptions
do not reveal
the natures of physical phenomena

Broadly perceptual processes
influence what seems obvious to you.

McCloskey et al. (1980, p. figure 2B)

McCloskey et al. (1980, p. figure 2D)

\section{Perceiving Impetus}

representational momentum

Sometimes when adult humans observe a moving object that disappears, they will misremember the location of its disappearance in way that reflects its momentum; this effect is called _representational momentum_ (Freyd & Finke, 1984; Hubbard, 2010).

The trajectories implied by representational momentum reveal that the effect reflects impetus mechanics rather than Newtonian principles (Freyd & Jones, 1994; Kozhevnikov & Hegarty, 2001; Hubbard, Blessum, & Ruppel, 2001; Hubbard, 2013). And these trajectories are independent of subjects' scientific knowledge (Freyd & Jones, 1994; Kozhevnikov & Hegarty, 2001). Representational momentum therefore reflects judgement-independent expectations about objects’ movements which track momentum in accordance with a principle of impetus.% \footnote{ Note that momentum is only one of several factors which may influence mistakes about the location at which a moving object disappears (Hubbard, 2005, p. 842). %: %\begin{quote} %`The empirical evidence is clear that (1) displacement does not always correspond to predictions based on physical principles and (2) variables unrelated to physical principles (e.g., the presence of landmarks, target identity, or expectations regarding a change in target direction) can influence displacement.' % %... % %`information based on a naive understanding of physical principles or on subjective consequences of physical principles appears to be just one of many types of information that could potentially contribute to the displacement of any given target' %\end{quote} }

Hubbard 2005, figure 1a; redrawn from Freyd and Finke 1984, figure 1

Hubbard 2005, figure 1b; drawn from Freyd and Finke 1984, table 1

**Representational momentum suggests that there are automatic processes which predict the future trajectories of physical objects.**

Kozhevnikov & Hegarty (2001, figure 1)

Fix shape and density. How would increasing the object’s size affect how quickly it decelerates when launched vertically? Impetus: larger size entails greater deceleration (so slower ascent). Newtonian: larger size entails lower deceleration (so faster ascent) if considering air resistance; otherwise size makes no difference.

simplified from Kozhevnikov & Hegarty (2001)

But even more convincingly, the prediction generated by Kozhevnikov and Heggarty’s conjecture about the computational description of the system underpinning representational momentum has been directly confirmed.

So while not decisive, I take this to be strong evidence for a **vertical distinction** between two systems for physical cognition.

speed vs accuracy

Since this is an important point for me, let me repeat: any broadly inferrential process must make a trade-off between speed and accuracy.

Henmon (1911, table 2)

speed vs accuracy:

Here you see the results of an old experiment by Henmon who had subjects judge which of two only very slightly different lines was longer. He noted that ‘under each category of judgment the wrong judgments are in general shorter’.

‘the wrong judgments are in general shorter’

This experiment doesn’t provide evidence for a speed-accuracy trade off and wasn’t designed to (speed was not experimentally manipulated). But it’s interesting that the idea of a speed-accuracy trade-off goes back such a long way.

Henmon p. 195: ‘A continuation of this investigation (1) where the time of exposure of stimuli was limited, (2) where the time of judgment was voluntarily shortened or prolonged, (3) and with varying differences in stimuli, should give significant results. footnote: The writer had planned such an investigation, but a change of work has necessitated its indefinite postponement; hence the publication of these preliminary results.’

**The value of having two systems which process inputs from a single domain arises from this trade-off.** Having multiple systems enables complementary trade-offs to be made. So it is not obvious that there could not be two systems both of which can predict the trajectories of moving objects.

process	priority	content (physics)	content (ethics)
fast	utility over consistency	impetus	Thomson-esque
slow	consistency over utility	Newtonian	???

They were led to a conjecture about the computational description by reflection on the fact that **any broadly inferrential process must make a trade-off between speed and accuracy**.

‘To extrapolate objects’ motion on the basis of [e.g. Newtonian] physical principles, one should have assessed and evaluated the presence and magnitude of such imperceptible forces as friction and air resistance ... This would require a time-consuming analysis that is not always possible.

‘In order to have a survival advantage, the process of extrapolation should be fast and effortless, without much conscious deliberation.

‘Impetus theory allows us to extrapolate objects’ motion quickly and without large demands on attentional resources.’

Kozhevnikov and Heggarty (2001, p. 450)

ethics?

If we applied Thomson’s method (or Rawls’) in the case in attempting to discover things about the physical world, we would unable to do things like landing a robot on a comet.

process	priority	content (physics)	content (ethics)
fast	utility over consistency	impetus	Thomson-esque
slow	consistency over utility	Newtonian	???

where’s the argument?

I have given no argument at all yet. This is just a preview.

consequences?

Could scientific discoveries concerning moral psychology undermine, or support, ethical principles?

No!

No more than in the physical case

Doesn't this contradict what you said about Foot? No: that was conditional on Foot’s method of trolley cases being a good one. Which it is not.

Could scientific discoveries concerning moral psychology change how humans do ethics?

Maybe.

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