What is the symbolism of the candle in the poem, The Apparition?

The taper, or candle, symbolizes mortality. The speaker tells the lady that, when he comes to her bedside as a ghost, "Then thy sick taper will begin to wink" (6). Here, the speaker paints a portrait of the future in which the lady's candle will flicker as he appears. But the candle also represents the lady's own fleeting life, for according to the speaker, she is soon to join him as a "ghost."