Older equivalent to “concrete thought” metaphor?

What came first, concrete as a way to express a solid thought, or concrete as a solid building material?

And what I am really getting at is, prior to the invention of concrete as a building material, was there a different metaphor used to express the idea of a concrete thought?

Solution 1:

The answer can be found in a dictionary where there is a comprehensive discussion of the word and you can see that it has a long history meaning "solid", "not abstract" and so on. From its Latin origin meaning "grow together" its main meaning is "solid, stuck together".

It is the logical opposite of discrete (in separate parts) although it is not used as an antonym.

Solution 2:

"Rock solid" should do the trick.

He used "rock solid" reasoning.

https://www.thefreedictionary.com/rock+solid

Of course you could use "solid as a rock" in the same context. I'm not sure which came first.

https://idioms.thefreedictionary.com/solid+as+a+rock