Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Conlin 858 M Presentation

505 views

Published on

Some philosophers have doubted the role of causation in science. Here I defend the position that causation is part of mature science.

  • Be the first to comment

  • Be the first to like this

Conlin 858 M Presentation

  1. 1. Causation: Not Just for Common Folk<br />Luke Conlin<br />1<br />
  2. 2. PREFACE:The importance of mechanism in science is important to convey in science education<br />2<br />
  3. 3. Many philosophers have doubted the need for causal talk in science…<br />3<br />“…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)<br />
  4. 4. …but the function of science seems to hinge upon causal notions.<br />4<br />
  5. 5. Norton says causal talk amounts to folk science, like “force” or “caloric”…<br />5<br />
  6. 6. …but I will show three ways that causal talk contributes to mature science<br />6<br />
  7. 7. I conclude that causation can (and does) play a central role in science.<br />7<br />
  8. 8. Causation can put “direct” causal restrictions on theories<br />As enforced by mathematically expressible principles<br />8<br />
  9. 9. Causal principles can underwrite theoretical derivations and empirical tests<br />9<br />
  10. 10. Fluctuation Theorem: using causality to derive 2nd law of thermodynamics<br />10<br />Evans, D. J., & Searles, D. J. (1996). Causality, response theory, and the second law of thermodynamics. Physical Review E, 53(6), 5808-5815.<br />
  11. 11. Causal Dynamical Triangulations: using causality to recover 4-D spacetime from quantum gravity<br />“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)”<br />11<br />Jurkiewicz, J., Loll, R., Ambjorn, J., & Concepts, K. (2008). Using causality to solve the puzzle of quantum space-time. Scientific American.<br />
  12. 12. Causation can put “indirect” restrictions on theories<br />By providing warrant for throwing out spurious solutions<br />12<br />
  13. 13. There are more mathematical solutions than there are physical ones<br />13<br />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?<br />Answer #1: <br /> 2.1 seconds<br />Answer #2:<br /> -.096 seconds<br />physically unreasonable!<br />
  14. 14. There are always more solutions to equations than obtain in the real world<br />Banks, T. (1985). T C P, QUANTUM GRAVITY, THE COSMOLOGICAL CONSTANT AND ALL THAT... Nuclear Physics B, 249, 332–360.<br />Burke, W. L. (1970). Runaway solutions: remarks on the asymptotic theory of radiation damping. Physical Review A, 2(4), 1501–1505.<br />Goldberger, M. L., & Treiman, S. B. (1958). Decay of the pi meson. Physical Review, 110(5), 1178–1184.<br />Ishak, M., Chamandy, L., Neary, N., & Lake, K. (2001). Exact solutions with w modes. Physical Review D, 64(2), 24005.<br />Magueijo, J., Albrecht, A., Coulson, D., & Ferreira, P. (1996). Doppler peaks from active perturbations. Physical Review Letters, 76(15), 2617–2620.<br />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.<br />Neary, N., Ishak, M., & Lake, K. (2001). The Tolman VII solution, trapped null orbits and w-modes. Arxiv preprint gr-qc/0104002.<br />Simon, J. Z. (1990). Higher-derivative Lagrangians, nonlocality, problems, and solutions. Physical Review D, 41(12), 3720–3733.<br />
  15. 15. Causality can provide warrant for rejecting spurious solutions<br />Clapp, R. E. (1968). Enforcing causality in numerical solutions of Maxwell&apos;s equations. Proceedings of the IEEE, 56(3), 329-329.<br />Fowler, M., & Maki, K. (1967). Conditions for Bound States in a Superconductor with a Magnetic Impurity. Physical Review, 164(2), 484-488.<br />Peebles, G. H., & Clapp, R. E. (1968). Comments on&quot; Enforcing causality in numerical solutions of Maxwell&apos;s equations. Proceedings of the IEEE, 56(8), 1365-1365.<br />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.<br />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.<br />Worster, M. G. (2006). Solidification of an alloy from a cooled boundary. Journal of Fluid Mechanics Digital Archive, 167, 481-501.<br />15<br />
  16. 16. Norton’s dome is a prime example of using causation to reject spurious solutions<br />16<br />A ball of unit mass sits at rest on top of a dome. What happens?<br />initial conditions:<br />initial conditions:<br />Answer #1: Nothing.<br /> r(t) = 0, for all T<br />Answer #2: It slides down the side after an arbitrary time T<br /> r(t) = 0, for t ≤ T<br /> r(t) = (1/144)(t-T)4 for t ≥ T<br />physically unreasonable!<br />
  17. 17. Causation can put “semantic” restrictions on scientific theories<br />By constraining the directionality of the causal model & thus the kinds of problems that can be solved with it.<br />17<br />
  18. 18. Pinker shows how causation can put semantic restrictions on language<br />Foregrounding is syntactical…<br />…But Foregrounding is semantically constrained<br />18<br />
  19. 19. Lorentz causal model places semantic restrictions on physics<br />“A-Problems”<br />“B-Problems”<br />19<br />
  20. 20. Einstein’s derivation of G.R. hinged on Lorentz causal model<br />20<br />OP*(POTENTIAL)=SOURCE<br />Core Operator, Entwurf Operator, <br />Ricci Tensor, <br />Einstein Tensor, etc…<br />(Renn et al., 2007)<br />
  21. 21. Have we satisfied the first horn of Norton’s argument?<br />21<br />
  22. 22. Potential objection: no universally exceptionless principle of causation…<br />22<br />
  23. 23. Norton calls causation “folk science” because it makes no real difference<br />23<br />We know that in classical physics vacua have no active powers, yet we routinely attribute to them<br />the ability to draw things in—to suck.<br />
  24. 24. …but I have shown three ways that causation is more than folk science.<br />24<br />
  25. 25. THANK YOU!!<br />Thanks to Lindley Darden & all of you in PHIL 858m for hearing me out!<br />Thanks to Matthias Frisch, as well as the UMD physics education research group for helpful discussions<br />25<br />
  26. 26. References<br />26<br />Clapp, R. E. (1968). Enforcing causality in numerical solutions of Maxwell&apos;s equations. Proceedings of the IEEE, 56(3), 329-329.<br />Fowler, M., & Maki, K. (1967). Conditions for Bound States in a Superconductor with a Magnetic Impurity. Physical Review, 164(2), 484-488.<br />Peebles, G. H., & Clapp, R. E. (1968). Comments on&quot; Enforcing causality in numerical solutions of Maxwell&apos;s equations. Proceedings of the IEEE, 56(8), 1365-1365.<br />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.<br />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.<br />Russell, B. (1957). Mysticism and logic. Garden City, N.Y.: Doubleday.<br />Wismer, M. G., & Ludwig, R. (1995). An explicit numerical time domain formulation to simulate pulsedpressure waves in viscous fluids exhibiting arbitrary frequency powerlaw attenuation. Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on, 42(6), 1040-1049.<br />Worster, M. G. (2006). Solidification of an alloy from a cooled boundary. Journal of Fluid Mechanics Digital Archive, 167, 481-501.<br />

×