Thomas Jefferson wrote, "I am not an advocate for frequent changes in laws and constitutions, but laws and institutions must go hand in hand with the progress of the human mind. As that becomes more developed, more enlightened, as new discoveries are made, new truths discovered and manners and opinions change, with the change of circumstances, institutions must advance also to keep pace with the times. We might as well require a man to wear still the coat which fitted him when a boy as civilized society to remain ever under the regimen of their barbarous ancestors."
James Madison: "I entirely concur in the propriety of resorting to the sense in which the Constitution was accepted and ratified by the nation. In that sense alone it is the legitimate Constitution. And if that is not the guide in expounding it, there may be no security for a consistent and stable, more than for a faithful exercise of its powers. If the meaning of the text be sought in the changeable meaning of the words composing it, it is evident that the shape and attributes of the Government must partake of the changes to which the words and phrases of all living languages are constantly subject. What a metamorphosis would be produced in the code of law if all its ancient phraseology were to be taken in its modern sense."
Sources:
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http://www.constitution.org/jm/18240625_lee.txt (Madison's letter to Henry Lee.)