Science has long been in the value business. Despite a widespread belief to the contrary, scientific validity is not the result of scientists abstaining from making value judgments; rather, scientific validity is the result of scientists making their best efforts to principles of reasoning that link their beliefs to reality, through reliable chains of evidence and argument. This is how norms of rational thought are made effective... The answer to the question "What should I believe, and why should I believe it?" is generally a scientific one.
Sam Harris