noun
assumption
uh-SUHMP-shun/əˈsʌmpʃn/
A belief accepted as true without proof.
He makes the assumption that the closed biscuit tin contains cookies.

Etymology
The pieces form a noun of “taking to oneself,” hence acceptance or adoption. In reasoning, an assumption is a proposition taken as a premise or accepted as true without proof.
In context
consciousness is a product of brain function. That was just an never proven uh assumption, never proven hypothesis. And um everybody thought it was true
More examples
- That assumption turned out to be wrong.
- We tested the assumptions behind the plan.
- Her argument rested on a doubtful assumption.
Forms
assumption · assumptions
Similar words
- presumption
- Often suggests a belief adopted as a starting position.
- supposition
- Supposition emphasizes a tentative idea rather than an accepted starting belief.