Why might a firm want to produce its goods even after diminishing marginal returns have set in and marginal cost is rising?

Diminishing marginal returns is
something that is always present in any kind of productive process. For all other
conditions remaining constant the increase in one factor of production will not continue
to increase production by the same extent and the decrease in the change is known as
diminishing marginal returns.

The increasing marginal cost
also cannot be looked at in isolation. It has to be looked at in terms of what the
difference between marginal revenue and the marginal cost is. The difference can be
allowed to decrease till marginal cost is equal to marginal revenue. Production should
not be increased beyond the point when the marginal cost and marginal revenue is equal
as that will not increase the total returns.

So a firm can
produce goods even if there is diminishing marginal returns and the marginal cost is
rising based on and because of what the value of the difference between the marginal
revenue and the marginal cost is.