The sentence immediately after it is a paraphrase of the sentence in your quotation:
To make a deliberative judgment based on a mere unreliable feeling is a different mistake from experiencing a reliable feeling and arriving at an incorrect conclusion through an error in deliberative judgment.
To make a judgment based on a not reliable feeling is a different mistake from experiencing a reliable feeling and drawing an incorrect conclusion through an error in judgment.
or presented like this:
the process of making a judgement on a feeling: not reliable feeling → judgement that ends up being wrong because of some unreliable feeling data is not the same mistake as reliable feeling → judgement that is an incorrect judgement.
The sentence immediately after it is a paraphrase of the sentence in your quotation:
Is that also too complex?
try this:
To make a judgment based on a not reliable feeling is a different mistake from experiencing a reliable feeling and drawing an incorrect conclusion through an error in judgment.
or presented like this:
the process of making a judgement on a feeling:
not reliable feeling → judgement that ends up being wrong because of some unreliable feeling data
is not the same mistake as
reliable feeling → judgement that is an incorrect judgement.