That may be true, but that doesn't make it valid reasoning. You should only use it with an explicit acknowledgement that your intention is to end the conversation (perhaps in a manner similar to that proposed by Dagon), without pretending that it is somehow an argument in its own right.

And even then, it should be used very sparingly. I'd be suspicious of any belief I hold if I can't remember why I hold it (if "the training data [was] thrown away").