We know organisms only as wonderfully integrated wholes, and we know
inheritance only as an inheritance of whole cells. This truth was
obscured during the era of genes and molecular biology, when
biologists came to see genes as substitutes for cells and organisms.
But the consequence of this was that biologists lost sight of the
central problem of inheritance — how an organism’s unified character
and entire way of being are passed on to its offspring. We will need
to recover our sight of that problem before we can make fundamental
progress in understanding evolution.