Luke Conlin

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There is a growing emphasis on learning through ‗inquiry‘; i.e. authentic scientific practices (NRC 1996)

UMD perg ‗defines‘ science as the pursuit of causal mechanisms

Mechanism has been underemphasized in science education

It has been possible to succeed through college science while holding wildly wrong conceptual ideas

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―…the reason why physics has ceased

to look for causes is that, in fact, there

are no such things. The law of

causality…is a relic of a bygone age,

surviving, like the monarchy, only

because it is erroneously supposed to

do no harm.‖ (Russell, 1913)

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First horn

EITHER causation places restrictions on factual content

of science…

We must find some factual restriction that can be applied

across all sciences…

Second horn

OR it does not

causation is an empty honorific

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DirectlyThrough

mathematical conditions

Indirectly

Through warrants for

applying solutions

Semantically

Through rules that constrain the physical

model

Tool for solving biggest theoretical

problems

Generativity in finding new laws

Tool for applying theory empirically

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As enforced by mathematically expressible principles

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No input before output

No interaction via spacelike intervals

No action-at-a-distance

No backwards causation

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Evans, D. J., & Searles, D. J. (1996). Causality, response theory, and the second

law of thermodynamics. Physical Review E, 53(6), 5808-5815.

―Restricted by Principle of Causality: When physicists add the rule

that adjacent triangles must have a consistent notion of time—so that

cause and effect are unambiguously distinguished—the outcome is a

four-dimensional space­time that looks tantalizingly like our universe.

(below)‖

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Jurkiewicz, J., Loll, R., Ambjorn, J., & Concepts, K. (2008). Using causality to

solve the puzzle of quantum space-time. Scientific American.

By providing warrant for throwing out spurious solutions

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You throw a rock into the air

at 10 m/s from 1 m above

the ground. How long will

it take to hit the ground?

00

2

2

2

2

1ytvgty

dt

ydmF

Answer #1:

2.1 seconds

Answer #2:

-.096 seconds

physically

unreasonable!

Banks, T. (1985). T C P, QUANTUM GRAVITY, THE COSMOLOGICAL CONSTANT AND ALL THAT... Nuclear Physics B, 249, 332–360.

Burke, W. L. (1970). Runaway solutions: remarks on the asymptotic theory of radiation damping. Physical Review A, 2(4), 1501–1505.

Goldberger, M. L., & Treiman, S. B. (1958). Decay of the pi meson. Physical Review, 110(5), 1178–1184.

Ishak, M., Chamandy, L., Neary, N., & Lake, K. (2001). Exact solutions with w modes. Physical Review D, 64(2), 24005.

Magueijo, J., Albrecht, A., Coulson, D., & Ferreira, P. (1996). Doppler peaks from active perturbations. Physical Review Letters, 76(15), 2617–2620.

Mason, J. K., Lund, A. C., & Schuh, C. A. (2006). Determining the activation energy and volume for the onset of plasticity during nanoindentation. Physical Review B, 73(5), 54102.

Neary, N., Ishak, M., & Lake, K. (2001). The Tolman VII solution, trapped null orbits and w-modes. Arxiv preprint gr-qc/0104002.

Simon, J. Z. (1990). Higher-derivative Lagrangians, nonlocality, problems, and solutions. Physical Review D, 41(12), 3720–3733.

Clapp, R. E. (1968). Enforcing causality in numerical solutions of Maxwell's equations. Proceedings of the IEEE, 56(3), 329-329.

Fowler, M., & Maki, K. (1967). Conditions for Bound States in a Superconductor with a Magnetic Impurity. Physical Review, 164(2), 484-488.

Peebles, G. H., & Clapp, R. E. (1968). Comments on" Enforcing causality in numerical solutions of Maxwell's equations. Proceedings of the IEEE, 56(8), 1365-1365.

Pi, T. W., Hong, I. H., Cheng, C. P., & Wertheim, G. K. (2000). Surface photoemission from Si (100) and inelastic electron mean-free-path in silicon. Journal of Electron Spectroscopy and Related Phenomena, 107(2), 163-176.

Wismer, M. G., & Ludwig, R. (1995). An explicit numerical time domain formulation to simulate pulsed pressure waves in viscous fluids exhibiting arbitrary frequency power law attenuation. Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on, 42(6), 1040-1049.

Worster, M. G. (2006). Solidification of an alloy from a cooled boundary. Journal of Fluid Mechanics Digital Archive, 167, 481-501.

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A ball of unit mass sits at rest on top of a dome. What happens?

Answer #1: Nothing.

r(t) = 0, for all T

Answer #2: It slides down the

side after an arbitrary time

T

r(t) = 0, for t ≤ T

r(t) = (1/144)(t-T)4 for t ≥ T

initial conditions:

1

0)0(

0)0(

m

r

r

2

2

dt

rdmF

2

2

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dt

rdr

initial conditions:

physically

unreasonable!

By constraining the directionality of the causal model & thus the

kinds of problems that can be solved with it.

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Load paper into the printer.

Load the printer with

paper.

Spray Windex onto the mirror.

Spray the mirror with Windex.

Feed bread to the

guests.

Feed the guests with

bread.

I riddled Capone

with bullets.

I riddled bullets into Capone.

I dripped water onto the floor.

I dripped the floor

with water.

I poured Pepsi into the glass.

I poured the glass

with Pepsi.

“A-Problems” “B-Problems”

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Field Equation

• field is foregrounded

• Changes the state of space

Equation of Motion

• particle is foregrounded

• Changes the trajectory of particle

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(Renn et al., 2007)

OP*(POTENTIAL)=SOURCE

Core Operator,

Entwurf Operator,

Ricci Tensor,

Einstein Tensor,

etc…

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First horn

EITHER causation places restrictions on factual content

of science…

We must find some factual restriction that can be applied

across all sciences…

Second horn

OR it does not

causation is an empty honorific

• Norton proposes energy as an example

Is there any such principle?

• Even conservation of energy is non-universal

I argue there is not • Either Norton

must provide a good example or concede

This requirement is too restrictive

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We know that in classical

physics vacua have no active

powers, yet we routinely

attribute to them

the ability to draw things in—to

suck.

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DirectlyThrough

mathematical conditions

Indirectly

Through warrants for

applying solutions

Semantically

Through rules that constrain the physical

model

Thanks to Lindley Darden & all of you in

PHIL 858m for hearing me out!

Thanks to Matthias Frisch, as well as the

UMD physics education research group for

helpful discussions

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Clapp, R. E. (1968). Enforcing causality in numerical solutions of Maxwell's equations. Proceedings of the IEEE, 56(3), 329-329.

Fowler, M., & Maki, K. (1967). Conditions for Bound States in a Superconductor with a Magnetic Impurity. Physical Review, 164(2), 484-488.

Peebles, G. H., & Clapp, R. E. (1968). Comments on" Enforcing causality in numerical solutions of Maxwell's equations. Proceedings of the IEEE, 56(8), 1365-1365.

Pi, T. W., Hong, I. H., Cheng, C. P., & Wertheim, G. K. (2000). Surface photoemission from Si (100) and inelastic electron mean-free-path in silicon. Journal of Electron Spectroscopy and Related Phenomena, 107(2), 163-176.

Renn, J., Janssen, M., Norton, J. D., Sauer, T., Stachel, J., Divarci, L., et al. (2007). The Genesis of General Relativity. The Genesis of General Relativity, in 4.

Russell, B. (1957). Mysticism and logic. Garden City, N.Y.: Doubleday. Wismer, M. G., & Ludwig, R. (1995). An explicit numerical time domain formulation to

simulate pulsedpressure waves in viscous fluids exhibiting arbitrary frequency powerlawattenuation. Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on, 42(6), 1040-1049.

Worster, M. G. (2006). Solidification of an alloy from a cooled boundary. Journal of Fluid Mechanics Digital Archive, 167, 481-501.