Think, for a moment, of a cheetah, a sleek, beautiful animal, one of the fastest on earth, which roams freely on the savannas of Africa. In its natural habitat, it is a magnificent animal, almost a work of art, unsurpassed in speedor grace by any other animal. Now, think of a cheetah that has been captured and thrown into a miserable cage in a zoo. It has lost its original grace and beauty, and is put on display for our amusement. We see only the broken spirit of the cheetah in the cage, not its original power and elegance. The cheetah can be compared to the laws of physics, which are beautiful in their natural setting. The natural habitat of the laws of physics is higher-dimensional space-time. However, we can only measure the laws of physics when they have been broken and placed on display in a cage, which is our three-dimensional laboratory. We can only see the cheetah when its grace and beauty have been stripped away.
As quoted by Michio Kaku in Hyperspace (Oxford University Press, 1994), p. 12. ISBN 0-385-47705-8.
Our understanding of the four basic concepts of Physics -- space, time, matter and force -- has undergone radical change in the course of work on unification, starting with Maxwell's unification of electricity with magnetism, all the way to present day string theory. What started as four independent concepts, with space and time postulated and the possible forms of matter and force arbitrarily chosen, now appear as different aspects of a rich and novel dynamically determined structure.
Physics and Geometry, a paper written for the Symposium on Theoretical Physics at the University of Helsinki, Helsinki, Finland on August 28, 2003 and at the Freydoon Mansouri Memorial Session of the 3rd International Symposium on Quantum Theory and Symmetries at the University of Cincinnati, Cincinnati, OH, on September 13, 2003. Report #EFI03-47.
Scientific collaborations are akin to marriages, or temporary marriages. Their breakup is not unlike a divorce and rarely avoids acrimony.
Peter G. O. Freund (2007). A passion for discovery. World Scientific. p. 89. ISBN 9812706461.