Why trademarks are different?

Trademarks are different from other immaterial monopoly rights that
government grants, because of their ultimate purpose is to prevent fraud,
not to prevent others from using an idea. Committing a fraud is to give
another person false information so that they would act in a way harmful
to their interests. By preventing me from selling jeans and claiming them
to be made by Levis, government does something good – it makes it less
profitable to harm people by leading them to bad actions. I should,
however, be allowed to make jeans that look alike, use the same sewing
techniques and same materials. But I should not falsely be entitled to
claim that they are made by Levis.

Thus, the trademark legislation may need change, but it should not be
completely abolished. The main purpose of government is to protect people
living on its lands from violence, theft, and fraud. This mission comes
from the fact that government holds monopoly over use of violence in its
territory and only that makes it possible to protect people from violence,
theft, and fraud. Government also takes on other duties, but none of them
can be considered as essential as those above, because at least in theory
it is possible for others to handle those duties. You may argue that not
in practice, but that is not relevant to what I say here, because the ones
impossible even in theory do take precedence over those that are possible
in theory (and maybe even in practice).

Thus, it is the duty of a government to create a society, which can reward
those who serve others well and punish those who would harm others.

Intellectual Monopoly Rights

Update: Can anyone of my readers provide a reason why patents should not be considered similar (from policy and law point of view) to establishing new trade routes?

Johan Norberg writes about intellectual monopoly rights in his blog.

The text of his makes me wonder, would he also have supported the
mercantilist system of giving monopoly for international trade of certain
items or trade routes? Would he consider that it was the right thing to
do, when the trade routes to Asia and America were being created – for a
limited period of time. To be fair, Norberg mostly speaks about copyrights
in his text, but the omission of patents gives the impression of them
being in the same category as copyrights, which he does not condemn.

The reason for asking is the patent laws. Patents are essentially
government granted trade monopolies for establishing a new trade route.
Not in the physical realm, but in the realm of ideas. And they work
exactly the same way as the mercantilist trade monopolies did. Once you
get the monopoly from government nobody else can trade there without your
permission. Not even if they travel there without any help from you or
your original trek.

I, as my readers may know, am opposed to the mercantilist trade monopolies
and see no difference between establishing new idea and establishing a new
trade route in an unknown world. The case for or against copyrights is a
lot murkier, but from liberal perspective, there should be no reason to
create and enforce government legislated monopolies, such as the trade
monopolies of past, or current patents.