“After long periods of error, philosophers have at last discovered the true rights of man and how they can all be deduced from the single truth: that man is a perceptive being capable of reason and acquiring moral ideas.

At last, man could proclaim his rights out loud, rights that for so long had been ignored. He could submit all opinions to his own reason and use that reason to search for truth. Every man learned with pride that nature had not forever condemned him to base his beliefs on the opinions of others or the superstitions of antiquity.

Thus developed an understanding that the natural rights of man are inalienable and cannot be forfeited and a strongly expressed desire for freedom of thought, trade, and profession. There also developed a desire to alleviate people's suffering, to eliminate all criminal laws against political dissenters, and to abolish torture. A desire arose for a milder system of criminal legislation that could give complete security to the innocent. All of these principles gradually filtered down from philosophical works to every class of society whose education went beyond basic literacy. These principles became the common faith of all people.”

Marquis de Condorcet, French nobleman and philosopher, Sketch for a Historical Picture of the Progress of the Human Mind, published in 1794

Which of the following is the main claim that the author makes in the passage?

The question above is related to "Marquis de Condorcet." He's a French philosopher who supports Enlightenment rationalism. He believes that people have the right to expand their knowledge. They can only do this through "rational inquiry" in order for them to analyze their own beliefs and understandings.

Besides this right, he was also an advocate regarding women's rights and the equality of men regardless of race, gender, culture and religion.

So, this explains the answer.