No, Traveller does NOT present them as having a scientific explanation. It doesn't explain them much; it just presents them as rules.
In both the 1977 and 1981 editions, the following text opens the chapter of Book 3 dealing with Psionics:
The powers of the mind are incredible; and some day the study of these powers will enable every individual to use them as an active part of his life. At the time in which Traveller occurs, however, universal psionic training does not exist; accurate information and quality training are available only through branches of the Psionics Institute, which is wholly devoted to the study of mental powers.
They are
powers of the mind. They are
studied by an
institute. And, in principle, everyone is able to learn these powers via training. To me it has always been clear that this is describing a type of scientifically-studied and comprehensible phenomenon, not supernatural ritual.
only because of a lack of nuance, there can be so many supernatural things that don't need to be connected to magic and spellcasting, like i said, distilling everything down to just being 'magic' is boring
it's like, imagine the avengers where they're all just wizards, tony doesn't have his suit he just knows fly and scorching ray, cap isn't a peak human or have his shield he just knows heroism and shield, thor isn't a god he just knows call lightning and spiritual weapon, black widow isn't a superspy she just knows pass without trace and charm person, hulk isn't a rage monster he just knows tenser's transformation and earth tremmor, hawkeye isn't a sharpshooter he just knows guiding bolt and swift quiver,
this is how it feels when people say 'it can all just be labelled magic'
I don't really follow.
I mean, I know that in the Marvel Universe science and magic are different phenomena. But there isn't a difference that I'm aware of between
magic and
the supernatural.
And your example also blends together flavour text and build elements in a particular way. I mean, in Hero/Champions (or some imaginable version thereof), I
would build Hawkeye by combining the "accurate shot* and "rapid shot" options, with a limit of "gear - bow and arrows"; would build Iron Man by combining the "flying" and "energy blast" options, with a limit of "gear - hi-tech suit of armour"; etc.
Somewhat similarly, in Rolemaster, which is an example of psionics/mentalism that has already been mentioned in this thread, there is no
mechanical difference between a Mentalist and a Magician except for some spell parameters, and the rules for being in different "realms" of magic, which mostly determine how armour, helmets and a lack of available hands penalise their casting,
I don't really subscribe to the position that
difference of flavour (ie psionics is distinct from tome-of-magic-style wizardry) has to mean a difference in how a PC is built, or how the actions declared for them are resolved.