In Mary Midgely's Heart and Mind chapter 9, she agrees with Philippa Foot that morality is defined by its seriousness, and its seriousness by a relation to our central purposes of life.

The need for a live morality still remains.

My main suggestion should now be becoming clear. I said that the central job done by 'moral', the job for which it was worth preserving, was to mark a certain sort of seriousness and importance, as in the remark, 'we can't just do what we fancy here; there is a moral question involved'. I have now tried to show how the word becomes fitted for this job, how it can mean 'belonging to a man's character, to his central system of purposes', and I have argued that the job is an essential one. I have suggested that Johnson's alternative of pinning it to certain recognized practices is a dead end. I have said that I do not at all mind another word being substituted for moral if anyone can find a better one, but that I suspect any other word will at present run into the same sort of problems. To develop the suggested meaning further, I shall now ask, what is this special kind of seriousness or importance? What is a serious matter? A serious matter is one that affects us deeply.

This is not the same as giving us a strong sensation; a sudden violent toothache which never recurs is not a serious matter, nor is the taste of pepper, whereas a persistent apathy, an absence of all strong sensations, would be very serious indeed. Not everything with lasting effects will qualify; a chronic complaint need not be serious. This is interesting; we can say, 'Yes, his rheumatism is bad, it would be serious for some people but it really isn't for him'. If his purposes in life do not involve much moving around, rheumatism is not serious; if he is a dancer, a sore toe may be. What is serious affects something central among his systems of purposes and it is that system we need to know about. Its variation, however, has limits. Any approach to total paralysis, total solitude, total destitution, total monotony, total confusion,universal hostility, is serious for anybody. You cannot claim that it is not so for a particular person simply as an odd fact, without giving an explanation, and it will have to be a good one. It is no use for instance simply saying, 'he chooses not to care about it'.

Explanation will have to move by describing an exceptional history, exceptional alternatives, and thereby a readiness to use an exceptional substitute for normal needs. ('He needs no human company because he talks with God/he lives in the past/he prefers seagulls/he is off his head anyway and can only talk to himself.') All this will be met with justified scepticism at first, melting only when we have grasped the complete picture of an accepted way of life. The same thing, of course,will be true if we are told that what is serious for him is the behaviour of a spider.Unless we are told how spiders come to matter so much (he is an entomologist, he isa spider-worshipper, he is Robert the Bruce) this is simply unintelligible, because seriousness involves connections with what is naturally important for a human being. This point seems needlessly complicated because many people, such as sociologists and existentialists, like to claim officially that there is no such thing as human nature, so that nothing is naturally any more important than anything else.This means that (for instance) total immobility or total solitude would be as good ways of life as any other, provided you either were brought up to them or decided to choose them. Man is supposed to be infinitely plastic.

I think this aspiration towards total openness is at the back of Hare's refusal to tie morality to a content. I find this contention so obscure (even a piece of plasticine is not infinitely plastic;everything has some internal structure) that I propose simply to wait till I find someone living by it; i.e. choosing such things, refraining from ever mentioning or appealing to human nature or instinct, not treating anything as naturally more important than anything else, avoiding Freudian argument, and (in particular)finding a way to reconcile their views with the actual behaviour of babies, before I start taking trouble about it. The fashion for infinite plasticity seems in fact to be on the way out in the social sciences.

Meanwhile, I propose to take it that we are so constituted as to mind more about some things than about others; that these distinctions can to some extent be traced, however much they are overlaid by training; that it is only among these things that we can make an intelligible choice; that an unintelligible choice is no choice at all, and that a connection with these things is of the essence of seriousness. Now what happens if we ask: is it not only a serious but a moral matter? My short and wild answer is that moral is simply the superlative of serious.