Some experiments, performed at Berkeley, Cologne, Florence, Vienna, Orsay a
nd Rennes led to the claim that something seems to travel with a group velo
city larger than the speed c of light in vacuum. Various other experimental
results seem to point in the same direction: For instance, localized wavel
et-type solutions of Maxwell equations have been found, both theoretically
and experimentally, that travel with Superluminal speed. Even muonic and el
ectronic neutrinos - it has been proposed - might be "tachyons," since thei
r square mass appears to be negative. With regard to the first-mentioned ex
periments, it was very recently claimed by Guenter Nimtz that those results
with evanescent waves or "tunneling photons" - implying Superluminal signa
l and impulse transmission - violate Einstein causality. In this note, on t
he contrary, we want to stress that all such results do not place relativis
tic causality in jeopardy, even if they refer to actual tachyonic motions:
In fact, special relativity can cope even with Superluminal objects and wav
es. For instance, it is possible (at least in microphysics) to solve also t
he known causal paradoxes, devised for "faster than light" motion, even if
this is not widely recognized. Here we show, in detail and rigorously, how
to solve the oldest causal paradox, originally proposed by Tolman, which is
the kernel of many further tachyon paradoxes. The key to the solution is a
careful application of tachyon mechanics, as it unambiguously follows from
special relativity.