"something inescapably points if ...." or "if something inescapably points to ..."?

Here "they are reluctant to accept the conclusions." Which conclusions? The conclusions "toward which such proof inescapably points" or, rewording, the conclusions "which such proof inescapably points" toward.

Notice that in the original sentence, the toward has been moved before the which. If you stick an extra to at the end as you have done in your attempted paraphrase, it's like saying the conclusions which such proof inescapably points toward to.

The structure is analogous to it's the job to which I'm dedicated vs it's the job which I'm dedicated to.

The if part simply says that they are reluctant to accept the conclusions if they don't sense (something).

The first is grammatical, if a little difficult to read, but the second makes no sense at all. You don’t need ‘inescapably points to’, because the subordinate clause is already introduced by ‘toward which’.

The meaning seems to me to be:

Proof inescapably points toward certain conclusions. They [these people] are reluctant to accept them [the conclusions] if they do not "sense" the uniformity themselves.

It remains an unsatisfactory statement, because there’s a mismatch between being reluctant to accept something and a failure to sense something else.

Your version is jumbled, as others have noted, because of an extra to.

Here is the original sentence in context:

Many people interested in human behavior do not feel the need for the standards of proof characteristic of an exact science; the uniformities in behavior are "obvious" without them. At the same time, they are reluctant to accept the conclusions toward which such proof inescapably points if they do not "sense" the uniformity themselves. But these idiosyncrasies are a costly luxury. – Skinner, Science and Human Behavior, 1953, p. 16

The context makes it clear that proof and uniformity while related are distinct, that is, are not different terms for the same thing. The meaning of the sentence may be expressed more clearly as follows:

At the same time, if they do not "sense" the uniformity themselves, they are reluctant to accept the conclusions toward which such proof inescapably points.

The author's wording is correct. For understanding, it helps to separate out the various parts.

At the same time, they are reluctant to accept the conclusions toward which such proof inescapably points if they do not "sense" the uniformity themselves.

They are reluctant
> at the same time
> to accept the conclusions
  > toward which such proof inescapably points
> if they do not "sense" the uniformity themselves.

You can take out any of those and still have a meaningful sentence (all of these preserve the author's original meaning, by the way):

They are reluctant.

They are reluctant at the same time.

They are reluctant to accept the conclusions.

They are reluctant to accept the conclusions toward which such proof inescapably points.

They are reluctant if they do not "sense" the uniformity themselves.

In other words, if is correct.