A more thorough explanation:

praesumitur pro negante (pronounced pri-zyoo-muh-tur proh ni-gan-tee) is a Latin phrase that means "it is presumed for the negative." This is a rule used by the House of Lords when the votes are equal on a motion.

For example, if there are 100 members in the House of Lords and 50 vote for a motion while 50 vote against it, the motion will be defeated because of the rule of praesumitur pro negante. This means that the House of Lords will presume that the negative side (those who voted against the motion) should win because they are the ones who are opposing the motion.

Another example is in a court case where the burden of proof is on the prosecution. If the prosecution cannot prove beyond a reasonable doubt that the defendant is guilty, then the defendant is presumed innocent. This is an application of the rule of praesumitur pro negante.

These examples illustrate how the rule of praesumitur pro negante works. It means that when there is doubt or uncertainty, the side that is opposing something is given the benefit of the doubt. This is because it is often easier to prove that something is false or wrong than it is to prove that it is true or correct.