Things he knew were not true, he knew could not be true [closed]

Things he knew were not true, he knew could not be true.

Is this a grammatical sentence?

I don't really know what material has been ellipted, so a bracket analysis would help.

Is this a grammatical sentence?

It is in the original form... but you have been lazy, and not quoted the whole, and the punctuation could be improved:

He argued things he knew were not true - he knew could not be true.

The "full" version would be:

He argued things that he knew were not true, and he argued things that he knew could not be true.

This is the transitive use to to argue:

OED

5. transitive. To bring forward the reasons for or against (a proposition, etc.); to discuss the pros and cons of; to treat by reasoning, examine controversially.

a1513 R. Fabyan New Cronycles Eng. & Fraunce (1516) I. lxxxxix. f. xxxix *The sayd causes warre well and sufficiently argued. * 1883 Marquis of Salisbury Speech in Lords 17 July I do not see that it is my business to argue the legal considerations adverted to.

He argued things he knew were not true, he knew could not be true.

The most obvious meaning of this sentence seems to be the following.

He showed that among the things that he knew there were some that were untrue and he knew that they could not be true, ie, that there was no possibility for them to be true. This is not a grammatical sentence, but it takes only the addition of "they" to make it correct (colloquial): there is no subject for the verb "to be". The ellipsis of "that" is common in informal style.

• He argued things he knew were not true, he knew they could not be true. (colloquial)

• He argued that things that he knew were not true, he knew that they could not be true. (formal)

The coordination is paratactic, (parataxis): in this sentence a simple comma is used.