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Assume vs Presume


  • ‘Assume’ (verb) means ‘take something as true in the absence of evidence’.
  • ‘Presume’ (verb) means ‘take something as true, with some degree of evidence’.

What’s the difference between ‘assume’ and ‘presume’?

At first sight, both words have the same broad meaning. So it’s easy to think they can be used interchangeably, but beware! That’s not strictly the case.

  • If you take something as true but without any real evidence to support your claim, use ‘assume’.
  • If there is some evidence, reason, or logic behind your claim, use ‘presume’.
  • Another meaning of ‘assume’ is to take on or adopt, as in a shape, characteristic, or duty.
  • In Law, another meaning of ‘presume’ is to accept something as true in the absence of proof that it is false.

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How they’re used

Example sentences with ‘assume’

  • We assume that x' > 0 and x" < 0.
  • Our projections assume a fertility decline that is below replacement-level fertility.

Example sentences with ‘presume’

  • They presumed consent for organ procurement.
  • These models inherently presume homogeneous uptakes.