How to analyse/parse 'what there are/is [noun] to [verb]'?

Question

Thanks to user oerkelens, I now understand the meaning of my quote, so ask NOT about it here. Yet this construct still mystifies and sounds wrong to me, so I'd like to decompose it further to naturalise it. Also, I only realised now that a worsening factor is 'there is'; I can endure the first three rewrites here:

[a man's gotta do (something)) -> What [a man's gotta do]
[(something) needs to be said] -> What [needs to be said]
[(some) vegetables were left] -> What [vegetables were left]
4. [there is evidence to believe (something)] -> What [there is evidence to believe]
5. [there is a reason to do (something)] -> What [there is a reason to do]

Please explain and show all steps, thought processes behind the arrows in 4 and 5? How does the left-hand side become the right-hand side?

Answer 1

The presence of there may sound wrong and strange, but it is correct and natural.

Even more important, it is essential in the sentence, because without it, what would refer to something else altogether!

Let's take an example situation:

I do this boring job because I need the money.

Obviously, there is a reason to do this boring job.

If I want to ask about a reason to do this boring job, I can ask:

What is a reason to do this boring job? I need the money.

What refers clearly to the reason here, and I'll assume you'll have little problem with the formation of that question.

Now, let's say that we know the reason, but we want to clarify what the reason logically entails: doing the job.

What there is a reason to do is this boring job.

Here, what refers to this boring job, not to the reason!

I can even leave out this boring job, and I could tell you that there are things I do for a reason (like that job), and there are things to do without an obvious reason, which I may enjoy much more:

What there is a reason to do is useful, but terribly boring.

To repeat the exercise with your original sentence: there is evidence to believe something. Let's say that you found a knife in my hand while I'm standing next to a dead rabbit in pieces in my kitchen.

It is likely I cut up the rabbit, but there is no evidence that the rabbit was alive when entering my kitchen — the likely assumption is that I bought it good and dead from a butcher!

If we talk about the evidence — my location and my holding a knife — we simply refer to that as:

The fact I was holding the knife is evidence to believe (I cut up the rabbit).
What is evidence to believe (I cut up the rabbit) is that I was holding a knife.

However, if you are talking about me cutting up the rabbit, what should not refer to the evidence!

There is evidence to believe I cut up the rabbit.
What there is evidence to believe is that I cut up the rabbit.

Answer 2

1. [a man's gotta do (X) ----------------> What [a man's gotta do ___ ]
   
2. [(X) needs to be said] ---------------> [What needs to be said]
   
3. [there is evidence to believe (X)] --> What [there is evidence to believe ___ ]
   
4. [there is a reason to do (X)] --------> What [there is a reason to do ___ ]
   

The phrases on the right are Noun Phrases. This means that they function in the sentence like a noun, usually as the Subject or Object of the sentence.

In the phrases on the right, the word what represents (X) from the examples on the left. There's a gap in the clause on the right, which is where the (what/X) moved from. In examples (3, 4) we could reconstruct the phrases so:

• What [there is reason to believe (it)]
• What [there is a reason to do (it) ]

We can then put these phrases into full sentences:

• 3' [What there is reason to believe ___ ] is that you've been eating all the pies.

• 4' [What there is a reason to do ___ ] is exactly what I shall do.

If this is still difficult to parse, this may help you: this particular word what means something like the thing which. In these clauses the thing is the element that is missing from the gap. So we understand that whole clause as being that missing thing.

Sentence 3' then means:

• The thing [which there is reason to believe [this thing]] is that you've been eating all the pies'.

Senetence 4' means:

• The thing [which there is reason to do [this thing]] is exactly what I shall do.

Hope this helps!