What is really being lost in wormholes?

We discuss a new general method to obtain the Tolman-Hawking wormhole instanton by simply providing the Robertson-Walker manifold with an extra three-sphere with a minimum radius equal to the Planck length. This topology change does not imply any unphysical value of the effective gravitational constant and requires a total energy which is no longer zero. It is argued that, even for wormholes with zero total energy, there is no loss of quantum coherence in the observable matter sector of flat spaces. The possibility that wormholes can induce chaotic behavior of spacetime is discussed by using a quantum-optical interpretation for wormhole interactions. Also discussed in the light of this interpretation is the Coleman mechanism for the vanishing of the cosmological constant and the fixing of physical coupling constants. A value zero is kept as the most probable value of the cosmological constant for large universes, but it is argued that the Coleman mechanism should be reinterpreted for small universes or the fixing of the coupling constants. It is also shown that the Wheeler-DeWitt equation for wormholes or little baby universes is reducible to a Klein-Gordon wave equation and that some of the solutions should be associated with antiwormholes, i.e., nontrivial topological changes with negative energy.