这句话本身就是一个真理：探究真理的相对性和主观性

It is not untrue to say that this sentence itself is a truth. We can find evidence for this in the fact that truth is often subjective and based on individual experience, meaning that what is true to one person might not be true to another. Therefore, when we say this sentence is a truth, we are acknowledging that it is true for us, even if it might not be true for someone else.

Moreover, truth is often very subjective and based on personal beliefs, values and even culture. For instance, in some cultures, it might be considered a truth that one should never lie, while in other cultures, it might be accepted that lying can sometimes be justified. Therefore, it is not untrue to say that this sentence itself is a truth, as it could be true for certain people, depending on their cultural or personal beliefs.

Furthermore, truth can also be relative and dependant on context. For example, in a certain context, one might consider it a truth that the world is round, while in another context, one might consider it a truth that the world is flat. Therefore, when we say that this sentence is a truth, we are acknowledging that it is true for us in this particular context, even if it might not be true for someone else in a different context.

In conclusion, it is not untrue to say that this sentence itself is a truth, as truth is often subjective, based on individual experience and beliefs, and can also be relative and dependant on context.