Weakness, invalidation, shaking, confutation, rebuttal, and enfeeblement Strengthen, confirm, fortify, and support are synonyms. The opposite of confirmation is weakening, which can be physical, such as a weak link in a chain-link fence; or mental, such as when someone weakens an argument against their position. Corroboration is the process by which facts that support or fail to support a hypothesis are used to determine if there is enough evidence to confirm the hypothesis. If more supporting evidence becomes available, then the hypothesis must be modified or replaced with another one. Corroborating evidence can come from different sources. For example, if an experiment yields contradictory results when performed multiple times, then we can be sure that the phenomenon being studied is not reliable. If the results of two experiments support each other's conclusions, then we can be certain that at least some of those conclusions are accurate. Corroborative evidence can also include observations made by others, such as eyewitness accounts or reports from third parties. In science, corroborating evidence is evidence that strengthens but does not completely prove our hypothesis. Only when all possible hypotheses have been considered and none found to account for all the evidence will we know that our theory is correct.