How arbitrary current notions concerning identity really are, may perhaps be perceived by reflecting upon some of the many different phases of reproduction.

Direct reproduction in which a creation reproduces another, the facsimile, or nearly so, of itself may perhaps occur among the lowest forms of animal life; but it is certainly not the rule among beings of a higher order.

A hen lays an egg, which egg becomes a chicken, which chicken, in the course of time, becomes a hen.

A moth lays an egg, which egg becomes a caterpillar, which caterpillar, after going through several stages, becomes a chrysalis, which chrysalis becomes a moth.

A medusa begets a ciliated larva, the larva begets a polyp, the polyp begets a strobila, and the strobila begets a medusa again; the cycle of reproduction being completed in the fourth generation.

A frog lays an egg, which egg becomes a tadpole; the tadpole, after more or fewer intermediate stages, becomes a frog.

The mammals lay eggs, which they hatch inside their own bodies, instead of outside them; but the difference is one of degree and not of kind. In all these cases how difficult is it to say where identity begins or ends, or again where death begins or ends, or where reproduction begins or ends.