Three buts are used in a row. Does it sound natural?

Personally, for the 2nd but I would say "only", and for the 3rd "then again"

But, but, but . . . this can't be serious ! ! !

I looked up the origin of the sentences.

In context, I like the way they read.

Not everything has to be written in dry ESL prose.

You may not like Hawking's writing style, but it is a style.

Thanks for confirming the Hawking Style.
I appreciate it.

It has a poetical, alliterative quality to it.

Indubitably.

Sorry Oristar. I'm disappointed in this thread. When I first noticed the title, I thought three butts in a row. That could be natural I suppose depending on circumstances.

butt butt butt

I also. The idea of "using" three butts in a row greatly intrigued me, even though at my age I would probably feel a little tired afterwards.

I think it's effective alliteration for an oratory.

I perceive a difference between the first two uses of 'but', where it is used as an equivalent for 'only', and the second, where it stands for 'however'. Whether this dilutes any oratorical effect is a possible topic for discussion. My own opinion is that it does.

I earn but a small salary, I live in but a small house, and I have but one pair of shoes. (Consistent)

I earn but a small salary, I live in but a small house, and I have but one pair of shoes. But I have a kind and loving family. (Not so consistent, and perhaps somewhat clumsy.) 'However' to start the second sentence might be more powerful. Bear in mind that Stephen Hawking was a professor of mathematics, not English.

Bear in mind that Strunk was a professor of English. I've run into a large number of professors of English who shouldn't go anywhere near expressing their opinions on the workings of language, especially others contemporaneous uses of the language.

There is a difference in the names of academic ranks between the US and the UK. In the UK, in a university department, there will usually be only one "Professor", who is the head of the academic staff, and who occupies a "chair", and is addressed formally as "Professor Surname". On the other hand, in US universities, a "professor" is a grade of teaching staff, a lecturer with "tenure" (a concept unknown to UK academia). Strunk was, as far as I can discover, one of these. Hawking was Lucasian Professor of Mathematics at Cambridge between 1979 and 2009.

The Lucasian Chair of Mathematics was founded in 1663 by Henry Lucas, who was Cambridge University's Member of Parliament from 1639–1640 and it was officially established by King Charles II on January 18, 1664. It is recognized as one of the most prestigious academic posts in the world and its former holders include Isaac Newton, Joseph Larmor, George Stokes and Paul Dirac. The latter was the neighbour of a friend of mine during her childhood, and was, apparently a very pleasant, unassuming and friendly man.

I see what you mean. That is an inconsistency up with which we shall not put.