The quote contrasts confident predictions of impossibility with the evidence created by someone who is actively attempting the task. Its humour comes from the reversal: the person who dismissed the goal should not obstruct the individual whose actions may prove that judgement wrong. The emphasis is therefore on allowing experience and effort to test assumptions.

More broadly, the remark favours initiative over premature certainty. It does not imply that every difficult objective can be achieved, but it cautions against treating scepticism as proof that something cannot be done. Progress often depends on people being willing to test limits that others regard as fixed. The quote can therefore be read as an argument for persistence, practical experimentation and intellectual humility, especially when established expectations are being challenged by someone prepared to act.