Why did the framers of the constitution create a mechanism for amending the constitution but then make it very difficult to actually make any changes?

The Framers of the Constitution create a mechanism for amending the Constitution but then make it very difficult to actually make any changes because they knew that it would be necessary to change certain parts of the constitution with time. What they wanted to avoid was people making changes as per their personal whims and so they made the process of change very difficult. 

It is meant that like tapestry scientific theories often need to pull out since they are not relevant and often times the whole chain of theories may be pulled out.