Quotes from John Leslie Mackie

the abandonment of a belief in objective values can cause, at least temporarily, a decay of subjective concern and sense of purpose. That it does so is evidence that the people in whom this reaction occurs have been tending to objectify their concerns and purposes, have been giving them a fictitious external authority. A claim to objectivity has been so strongly associated with their subjective concerns and purposes that the collapse of the former seems to undermine the latter as well.

The facts have to be determined by empirical evidence, and our thinking has then to conform to the facts, not the facts to our thinking

There are no objective values.

The difficulty of seeing how values could be objective is a fairly strong reason for thinking that they are not so

So far as ethics is concerned, my thesis that there are no objective values is specifically the denial that any such categorically imperative element is objectively valid.

the weather is such as I would favour if I were a potato-grower – or, more dubiously, if I were a potato.

The claim that values are not objective, are not part of the fabric of the world, is meant to include not only moral goodness, which might be most naturally equated with moral value, but also other things that could be more loosely called moral values or disvalues—rightness and wrongness, duty, obligation, an action's being rotten and contemptible, and so on. It also includes non-moral values, notably aesthetic ones, beauty and various kinds of artistic merit.

In Plato's theory the Forms, and in particular the Form of the Good, are eternal, extra-mental, realities. They are a very central structural element in the fabric of the world. But it is held also that just knowing them or 'seeing' them will not merely tell men what to do but will ensure that they do it, overruling any contrary inclinations.

In one important sense of the word it is a paradigm case of injustice if a court declares someone to be guilty of an offence of which it knows him to be innocent. More generally, a finding is unjust if it is at variance with what the relevant law and the facts together require, and particularly if it is known by the court to be so.

The denial that there are objective values does not commit one to any particular view about what moral statements mean, and certainly not to the view that they are equivalent to subjective reports.

It is a hard fact that cruel actions differ from kind ones, and hence that we can learn, as in fact we all do, to distinguish them fairly well in practice, and to use the words 'cruel' and 'kind' with fairly clear descriptive meanings; but is it an equally hard fact that actions which are cruel in such a descriptive sense are to be condemned?