Infinite regress arguments are usually used to demonstrate a reductio ad absurdum against a position.

For instance, the homunculus regress demonstrates the problem with saying that there is a little man in our brains in order to explain our experience. This is because we can similarly ask the same question of how this little man will have their experiences, and we will have to introduce another man inside that little man to explain their experience and so on and so forth.

Another, probably less known example is Mctaggart's regress against tensed theories of time (though I don't agree with it, I want to focus on it's structure). He tries to introduce a contradiction by saying that all events have the A-properties of being past, present, and future together simultaneously and then argues that this can only be avoided by saying that an event's being either past, present or future also has A-properties themselves. However, given that they have A-properties as well, then they will also be subject to the same contradiction and a regress ensues.

However, not all regresses are known to be problematic. Take for instance, the regress of truths. Suppose X is true. Then it is true that "X is true". But it will also be true that " 'X is true' is true", and so on and so forth. In this case we clearly have a regress, but we have no problem in accepting it. In other words, what we have here is a benign regress. The other two regresses above are vicious regresses and they are usually what we refer to when we talk about problematic regresses. So not all regresses are problematic, but what is the distinction between the two? What is difference between a vicious regress like the above and a benign regress?

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My guess: A vicious regress is one which is created to solve a problem whereas a benign regress isn't. In the two examples above, there is a question or problem that needs to be explained which prompts the introduction of a regress. In the homunculus regress it is the need to explain our experience and in Mctaggart's regress, it is the need to avoid his contradiction. The solution offered in both cases suffer from precisely the same problems as the initial setup, and thus requires a similar solution which in turn faces the same problem ad infinitum. The problem with these regresses is that no progress has been made at all with regards to the initial problem and because of that, the regress becomes frivolous. It is like the equivalent of taking one step forward and one step back an infinite number of times; you haven't made any progress at all.

In contrast the regress of truths was never introduced to explain or solve anything. We never had any problem to solve when beginning with the understanding that X is true so no problem exists. Instead, the regress was merely the logical result of the fact that X is true.