Generally, sentences are constructed like this:
Compared to Joe, he looks similar. Compared to Joe, he looks different. Compared to Joe, he looks handsome. Compared to Joe, he looks ugly.
Yet, when it comes to "same", a sentence would be considered ungrammatical if it was written as:
Compared to Joe, he looks same.
Instead, it should be written as:
Compared to Joe, he looks the same.
Is there a reason for this quirk?
I'm interested in the "why" of this topic. I wonder if this peculiar treatment of "same" developed due to functors that are synonymous with "same", such as "as". Just as functors are somewhat special in grammar, I wonder if that inclined special use of "same" in grammar too.