The Entail has, at its heart, three great characters. I mean really great, archetypes, if only people knew them. Claud Walkinshaw is one, the miserly Scot stricken by his conscience. His wife is another - Scott and Byron both single her out as an all-time classic.* But I want to look at their second son, Walter, or Watty. Because Walter presents some difficulties.
Walter is mentally handicapped, from birth. A "natural," people call him, or an idiot. They are aware of his condition because of his behavior, not his appearance, but I won't speculate about what it is, exactly. How many ways must there be to botch this character? Dickens does it twice, with Smike in Nicholas Nickleby and later, but not so badly, with Barnaby Rudge. Smike, especially, does not fit in his novel, and suffers the necessary fate. I wonder if Dickens knew The Entail? Because Walter Walkinshaw really lives in his novel.
At first Walter seems to be a plot device. He's the center of the novel's inheritance plot. But he has a will of his own, and a mind of his own. He never quite does what I expect him to do. He concludes, for example, that all of his father's secret scheming is an attempt to disinherit him in favor of his older brother, when it is in fact the reverse. He eventually does lose his inheritance, but to his cold-blooded younger brother, who has him declared mentally unfit:
The jury then turned round and laid their heads together; the legal gentleman spoke across the table, and Walter was evidently alarmed at the bustle. - In the course of two or three minutes, the foreman returned a verdict of Fatuity.
The poor Laird shuddered, and, looking at the Sheriff, said, in an accent of simplicity that melted every heart, "Am I found guilty? - O surely, Sir, ye'll no hang me, for I cou'dna help it?" (III. 21.)
This reader's heart melted, too. By this point in the novel, Walter's suffering is real enough. One more taste of Walter telling his brother George that he "dinna like big folk":
"And why not?"
"'Cause ye ken, Geordie, the law's made only for them; and if you an me had ay been twa wee brotherly laddies, playing on the gowany brae, as we used to do, ye would ne'er hae thought o' bringing yon Cluty's claw frae Enbro' to prove me guilty o' daftness."
"I'm sure, Watty," said George, under the twinge which he suffered from the observation, "that I could not do otherwise. It was required from me equally by what was due to the world and my mother."
"It may be sae," replied Walter; "but, as I'm daft, ye ken I dinna understand it;" and he again resumed his oscillations. (III. 24.)
A not uncommon reaction to Galt - I don't know another character quite like Walter.
* Galt's - The Entail's - most appreciative readers seem to have been Walter Scott, Lord Byron, and Samuel Taylor Coleridge (his marginaliaed copy of The Provost is extant). John Galt was apparently one of those "writers' writers."