To provide a convincing argument you must show that given your statement the opposite of your conclusion could not be true.
I think this is a matter of opinion and a personal requirement as opposed to anything universally shared as being accurate. Typically, I would agree but the windows to other possible realities still exist. Hermetic philosophy, for example, suggests a law of correspondence and a law of rhythm to be truth's. As above, so below relates to correspondence and pendulum swings relate to the tides of life, the in's and the out's, the this way's and that way's concept connoting fluid type dynamics, constant in life ... Newtons proportioned 3rd law, or maybe Einsteins special law of relativity combined.
These are old and some would say irrelevant and "outdated" philosophical teachings by a guy named Hermes Trismegistus, which oddly enough correspond nicely with some of this world's greatest scientific thinkers.
Anyway, true and untrue can both be true simultaneously, without dismissing the other as completely irrelevant. This embodies the hermetic law of polarity, suggesting that they are in actually both true and both untrue and the same.
If you're at all interested in where this is taught and how it can be applied, you can find it
here.
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