Pour Répondre à la question qui constitue le titre de cet essai, il faut d'abord répondre à une autre question, à savoir: qu'est-ce que la philosophie de la nature? De quoi parlons-nous au juste quand nous parlons de philosophie de la nature?

C'est un Radieux amour de jeunesse que celui de Hegel pour «la belle totalité grecque» et cet amour est d'autant plus profond que le monde moderne alentour craque et se déchire. Hegel qui, dans la jeune histoire de la philosophie, occupe une place originale par sa lecture interprétative des œuvres grecques, sait bien que la République platonicienne n'a pas dessein de décrire les champs élyséens de la Grèce primitive; mais il retrouve en elle la vie harmonique et la plénitude de cette communauté première qui, antérieure à l'Etat comme forme politique aussi bien qu'à la religion comme dogme, n'était qu'ordre et beauté en raison de l'intime entrelacs du politique et du religieux.

Ceux Qui Lisent l'Ecole de Francfort sont frappés par le caractère spéculatif de ses démarches: préférant se définir comme « philosophie sociale » et non comme sociologie elle semble bien accorder à la philosophie plus d'importance qu'à la société. A cette philosophie de l'émancipation on a donc plus d'une fois jeté à la tête – et c'est bien l'expression qui convient – qu'elle n'émancipe que dans la tête. Après la révolte étudiante de 1968, nombreux sont ceux qui ont considéré que l'Idée de la théorie critique s'était discréditée sur la scène de l'histoire.

Perhaps the Clearest and most impressive use of the Principle of Continuity by Leibniz in the evaluation of a theory is that offered in refutation of the Cartesian laws of motion, as given in his Critical Remarks Concerning the General Part of Descartes' Principles. With regard to the Cartesian laws of impact Leibniz says:

On Article 49. Rule 4. If B, which is moving, is smaller than C, which is at rest, B will be reflected with the velocity it had before the shock while C will remain at rest.

Any theory of reduction that goes only so far as carried in Parts I and II ([165], [166]) does only half the job. Prima facie at least, there are cases of would-be reduction which seem torn between two conflicting intuitions. On the one side there is a strong intuition that reduction is involved, and a strongly retentive reduction at that. On the other side it seems that the concepts at one level cross-classify those at the other level, so that there is no way to identify properties at one level with those at the other. There is evidence to suggest that there will be no unique mental state/neural state association that can be set up, because, e.g., many different parts of the nervous system are all capable of taking over ‘control’ of the one mental function. And it is alleged that infinitely many, worse: indefinitely many, different bio-chemo-physical states could correspond to the economic property ‘has a monetary system of economic exchange’; and similarly for the property ‘has just won a game of tennis’. Yet one doesn't want an economic system or a game of tennis to be some ghostly addition to the actual bio-chemo-physical processes and events involved (cf. Rudner [188]). Similarly one hopes that neurophysiology allied with the rest of natural science will render human experience and behaviour explicable.

In any discussion about evaluation, particularly in ethics and aesthetics, there always exists a small recalcitrant group denying any purpose to the enterprise. Although they may be called relativists or extreme subjectivists or some such name to distinguish them from others who seek the basis of merit in the ‘thing itself’, they are best characterized by the two slogans frequently touted in times of intractable disagreement. These are, of course, the suave Chacun à Son Goût and the more pontifical de Gustibus non Disputandum. The first is frequently tossed out when someone displays growing signs of disapproval at another's unrepentant preference, while the second takes the stage when he who disapproves attempts to alter the choice already made. The import of these slogans is that there is an impregnable, irreducible sovereignty in matters of taste.

In the essay “Justice and Rights” of his book Taking Rights Seriously Ronald Dworkin puts forward an account of reflective equilibrium which has become an orthodoxy in interpreting John Rawls' theory of justice. My purpose here is to challenge this account, on the grounds that it presupposes an untenable view of the relation between belief and choice.

Keynes introduces three different principles under the single title “the principle of indifference”. The first is Bernoulli's princple of non-sufficient reason.

If there is no known reason for predicating of our subject one rather than another of several alternatives, then relatively to such knowledge the assertions of each of these alternatives have an equal probability. Thus equal probabilities must be assigned to each of several arguments, if there is an absence of positive ground for assigning unequal ones.