Question re. Frances R. Dewing quote

Hi everyone, this quote is from "Humanism as the Next Step" by Lloyd and Mary Morain. I've put the part that's giving me trouble in bold.

"One of the essential things about scientific method is an open mind, critical only of the quality of the evidence, and a readiness to accept any conclusions. With this goes an eagerness to find the principles that can be used to give us successful dealings with our objective experiences. These principles as long as they work are what we call truth.

Contrasted with this basis for truth which assumes dependence on reasoning power there is truth by authority—personal, organizational or “by the book.”

This cleavage of method is a more fundamental cleavage than cleavage according to items of conclusions, especially as by our method any conclusion is conceivably possible. The only negative allowable is the denial of the right of any other person to assert a statement without showing reasons—especially to assert truth for others dogmatically.

What does Dewing mean by "items of conclusions?"

Full text can be found here: http://americanhumanist.org/what_we_do/publications/Humanism_as_the_Next_Step/Chapter_3:_Some_Basic_Beliefs