In proceedings to construe a will, evidence, including evidence of the testator's dispositive intention, is admissible to the extent that the language used in the will renders the will, or any part of the will—
(a) meaningless; or
(b) ambiguous or uncertain on the face of the will; or
(c) ambiguous or uncertain in the light of the surrounding circumstances;
but evidence of a testator's dispositive intention is not admissible to establish any of the circumstances referred to in paragraph (c).