There is no theoretical principle that cannot be put into practice because…

Concept

Begging the question is a circular fallacy: the reasoning assumes, restates, or presupposes the conclusion in a premise instead of supplying independent support for it.

A sound argument must give a reason whose acceptability does not already depend on accepting the conclusion.

Application

The conclusion is that every genuine theoretical principle can be put into practice. The stated reason says that any principle that cannot be put into practice is not a theoretical principle at all. This merely builds the conclusion into the definition of a theoretical principle, so it provides no independent support.

Contrast

• Slippery slope predicts an unsupported chain of worsening consequences; no such chain is proposed here.

• Straw man distorts another person’s position before attacking it; no opposing position is reconstructed here.

• Inappropriate authority relies on a source that lacks relevant expertise; the argument cites no authority.

• Begging the question uses its conclusion as part of its own support, which is the circular pattern present here.

Result

Therefore, the fallacy is begging the question.