The only viable explanation was that Fred had not slept.

The thermoregulatory model explaining the origin of bipedalism is one of the simplest theories so far advanced, but it is a viable explanation.

Sharif al-Murtaza (d. 1044) had similar views, turning to divine intervention as the only viable explanation as to why the challenge was not met.

In this strategy, all viable explanations are considered and contrasted to determine the most likely to be true.

However, viable alternative explanations always exist.

There would be no viable explanation for the presence of that chemical, they said, other than the production of VX.

Its the most viable explanation.

Compagnoni explains his decision to move the tent was to avoid an overhanging serac, a viable explanation.

The only viable explanation for the presence of the "precursor chemical" is the production of VX, the official said.

Yet "none provided a viable alternative explanation for the observed homicide trends."