On whether "practice is the only criterion for testing truth" is right or wrong.

Practice is not the criterion for testing truth.

1. Practice is the means and way to test the truth.

2. The criterion of truth is: "The knowledge of subject accords with the object".

Coincidence = correct reflection

Everything that conforms to (or correctly reflects) the understanding of the object is truth;

Any deviation (or false reflection) from the understanding of the object is fallacy.

3. The definition of truth contains the standard of truth.

Truth is the correct reflection of objective things and their laws.

Fallacy is a distorted reflection of objective things and their laws.