# Relativity

## Conclusion

Einstein's struggle to relativize all motion, uniform and nonuniform, illustrates the old travelers' saying that the journey is more important than the destination. Although Einstein never reached the destination he originally had in mind, he found many valuable results along the way. For starters, he fulfilled many of his philosophical hopes, albeit in ways very different from what he originally envisioned. Absolute motion survives in general relativity, since there is an absolute difference between moving on a geodesic and moving on a nongeodesic. But motion with respect to curved space-time with a geometry described by a field interacting with matter (itself described by other fields) is a much more agreeable proposition than motion with respect to the absolute space(-time) of Newtonian theory and special relativity. The combination of the hole argument and the point-coincidence argument, moreover, had provided a strong argument against a Newtonian substantival view of space-time and strong support for the rival Leibnizian relational view.

More importantly, Einstein had found a new theory of gravity, which does away with the artificial split between space-time and gravity of Newtonian theory. This theory opened up such exciting research areas as modern cosmology, black holes, singularities, gravitational waves, and gravitational lensing. Even some of the dead ends in Einstein's crusade against absolute motion led to interesting physics. In 2004, the National Aeronautics and Space Administration's (NASA) *Gravity Probe B* was trying to detect frame dragging, a phenomenon first investigated in the context of Einstein's misguided attempt to vindicate Mach's account of Newton's bucket experiment. The cosmological constant, originally introduced in the context of Einstein's ill-fated attempt to make general relativity satisfy Mach's principle, has made a spectacular comeback in modern cosmology as a straightforward phenomenological description of the repulsion driving the acceleration of the expansion of the universe discovered through Type Ia Supernovae observations. Einstein's quest for general relativity was a very rewarding journey indeed.

*See also* ** Cosmology: Cosmology and Astronomy**;

**Geometry**;

**Mathematics**;

**Newtonianism**;

**Physics**;

**Science, History of**;

**.**

*Science, Philosophy of*## BIBLIOGRAPHY

Alexander, H. G., ed. *The Leibniz-Clarke Correspondence.* Manchester, U.K.: Manchester University Press, 1956.

Barbour, Julian, and Herbert Pfister, eds *. Mach's Principle: From Newton's Bucket to Quantum Gravity.* Boston: Birkhäuser, 1995.

Dorling, Jon. "Did Einstein Need General Relativity to Solve the Problem of Absolute Space? Or Had the Problem Already Been Solved by Special Relativity?" *British Journal for the Philosophy of Science* 29 (1978): 311–323.

Earman, John. *World Enough and Space-Time: Absolute versus Relational Theories of Space and Time.* Cambridge, Mass.: MIT Press, 1989.

Einstein, Albert. *Ideas and Opinions.* New York: Crown, 1954.

——. *The Meaning of Relativity.* Princeton, N.J.: Princeton University Press, 1956.

——. *Relativity: The Special and the General Theory.* New York: Bonanza, 1961.

——. *Sidelights on Relativity.* New York: Dover, 1983.

Goenner, Hubert, et al., eds. *The Expanding Worlds of General Relativity.* Boston: Birkhäuser, 1999.

Howard, Don, and John Stachel, eds. *Einstein and the History of General Relativity.* Boston: Birkhäuser, 1989.

Janssen, Michel. "Reconsidering a Scientific Revolution: The Case of Einstein versus Lorentz." *Physics in Perspective* 4 (2002): 421–446.

——. "*COI* Stories: Explanation and Evidence in the History of Science." *Perspectives on Science* 10 (2002): 457–522.

Janssen, Michel, and John Stachel. "Optics and Electrodynamics in Moving Bodies." In John Stachel's *Going Critical.* Dordrecht: Kluwer, forthcoming.

Lorentz, Hendrik Antoon, et al. *The Principle of Relativity.* Translated by W. Perrett and G. B. Jeffery. New York: Dover, 1952.

Misner, Charles W., Kip S. Thorne, and John Archibald Wheeler. *Gravitation.* San Francisco: Freeman, 1973.

Niven, W. D., ed. *The Scientific Papers of James Clerk Maxwell.* 2 vols. Cambridge, U.K.: Cambridge University Press, 1890.

Norton, John. "Geometries in Collision: Einstein, Klein, and Riemann." In *The Symbolic Universe: Geometry and Physics, 1890–1930,* edited by Jeremy Gray. Oxford: Oxford University Press, 1999.

Pais, Abraham. *"Subtle Is the Lord …": The Science and the Life of Albert Einstein.* Oxford: Oxford University Press, 1982.

Renn, Jürgen, et al. *General Relativity in the Making: Einstein's Zurich Notebook.* Vol. 1 of *The Genesis of General Relativity: Documents and Interpretation.* 2 vols. Dordrecht: Kluwer, in preparation.

Rynasiewicz, Robert. "The Construction of the Special Theory: Some Queries and Considerations." In *Einstein: The Formative Years, 1879–1909,* edited by Don Howard and John Stachel. Boston: Birkhäuser, 2000.

Stachel, John, ed. *Einstein's Miraculous Year: Five Papers That Changed the Face of Physics.* Princeton, N.J.: Princeton University Press, 1998.

Stachel, John, et al., eds. *The Collected Papers of Albert Einstein.* 8 vols. Princeton, N.J.: Princeton University Press, 1987–2002.

*Michel* *Janssen*

## Additional topics

Science EncyclopediaScience & Philosophy: *Reason* to *Retrovirus*Relativity - Special Relativity, General Relativity, Conclusion, Bibliography