Hypothesis is a 1978 album by the Greek artist Vangelis. In May 1971 Vangelis had played several sessions in London's Marquee Studios, joined for some of them by violinist Michel Ripoche, bass guitarist Brian Odgers (called Odger on the sleeve) and drummer Tony Oxley, the rhythm section of the famous Extrapolation recording released by John McLaughlin. Two albums' worth of material had resulted from these sessions, but were unfinished and never intended for release. Nevertheless, in 1978 two albums duly appeared in shops, on the Affinity label (a subsidiary of Charly Records) Hypothesis and The Dragon. Vangelis subsequently took the label to court to have both LPs taken off the market. Hypothesis has critically been considered to be unsuccessful as an album.
Musically, the album can be considered to be Vangelis' most idiosyncratic and unusual release, as it takes the form of an extended experiment in experimental Jazz, or Jazz fusion.
An alternative release of Hypothesis was titled Visions of the Future.
In Germany Hypothesis and The Dragon were issued together as a double album titled Portrait.
The cover artwork for Hypothesis is by Angus McKie, and is merely a "borrowed" illustration he drew for a series of novels by SF author Brian Stableford, featuring the spacecraft Hooded Swan, mentioned in the books.