Not at all. An assumption is "a thing that is accepted as true or as certain to happen, without proof" [1]. The goal of science is minimize assumptions and ma

Not at all. An assumption is "a thing that is accepted as true or as certain to happen, without proof" [1]. The goal of science is minimize assumptions and maximize knowledge (justified, true belief) [2]. One easy way to do this is to make predictions: "If $THEORY is correct, then under the same conditions, I will observe $OUTCOME. If $OUTCOME does not obtain, I either haven't properly conducted the experiment, or $THEORY is wrong. 1. https://translate.google.com/#auto/en/assumption https://translate.google.com/#auto/en/assumption 2. https://en.wikipedia.org/wiki/Scientific_method https://en.wikipedia.org/wiki/Scientific_method EDIT: In response to your rephrasing of "if...then", to "assuming...then", consider that we actually do (or do not) observe $OUTCOME -- we don't assume that we observe it. To use an outrageous (but hopefully clear) example, do we know decapitation is fatal, or do we merely assume it? A long time ago (but in this galaxy) someone had a theory that decapitation was fatal. Experimentation gave us knowledge on this issue. Doubtless, they did not have The Scientific Method in mind, but they used the same process.