A presupposition is something that you assume to be true, especially something which you must assume is true in order to continue with what you are saying or thinking.
例句
...the presupposition that human life must be sustained for as long as possible.人的生命一定可以尽可能延长的假设
英汉词典释义
n.
假设的事情;假定;预设
Your judgment of the case is based on the presupposition that the witness is telling the truth.你对这案件的裁决,是以证人讲的都是实话这一假设为依据的。
英英词典释义
Noun
1. the act of presupposing; a supposition made prior to having knowledge (as for the purpose of argument)