I would say that the ending of the novel reflects hopelessness through Victor's eyes with the lack of totality inherently presented in Science. I think that the hopes and aspirations that Victor had in science at the outset of his narrative is replaced by a sense of hollowness at its conclusion. There is a lack of faith in Science in that it could not explain what the right thing to do is and could not answer how life should be lived. The element that formed the basis of Victor's consciousness is something that became absent at the end of it when the monster's destruction and Victor's lack of appropriate and proactive response was evident. In the end, this provides a sense of hopelessness when individuals lose faith in what guided them and where meaning is not easily evident.
In his letter of August 26th 17-, Walton writes to his sister that Victor Frankenstein must have been a noble creature in his days of prosperity, for he is
noble and godlike in ruin! He seems to feel his own worth and the greatness of his fall.
Victor likens himself to "the archangel" [Lucifer] who began with lofty ideals and a "high destiny," but whose pride and hubris which effected his fall, "never, never again to rise." His degradation and despair are due to his mistaken values. His science was elevated above all other values,
I trod heaven in my thoughts, now exulting in my powers, now burning with the idea of their effects.
This "lofty ambition,"as Victor says--a phrase suggestive of Macbeth's admission of "ambition that o'erleaps itself"--is the tragic flaw that causes him to mitigate the value of family and friends. Only too late, in his despair, does Victor Frankenstein realize their value far exceeds his ambition for science. He tells Walton,
Can any man be to me as Clerval was; or any woman another Elizabeth? Even where the affections are not strongly moved by any superior excellence, the companions of our childhood always possess a certain power over our minds which hardly an later friend can obtain.
Here Mary Shelley's character is the voice of his author. A Romanticist, Shelley and others like her, were concerned with the advances of science, and what their effects upon humanity and nature would be.