Flesh in the Age of Reason by Roy Porter Page B

the franchise and citizenship – all these required rulings as to who was to count as an independent unit, blessed and burdened with rights and responsibilities.
    The humanism of Shakespeare’s day prized self-knowledge. ‘My self am centre of my circling thought/Only myself I study, learn and know’, reflected Sir John Davies in his
Nosce teipsum
(1599), just before Shakespeare’s play recorded Polonius’s gratuitous advice to his son. For seventeenth-century philosophers, the solution to the riddle of identity would be sought along the road to knowledge. The self which could be known was necessarily the knowing self – the answer to the oracle’s
nosce teipsum
would come through exploration of
what
could be known about existence at large and
how
. Rejecting alike the chop-logic
ex cathedra
metaphysics of churchmen and schoolmen, and the sceptical seductions of gentlemanly Pyrrhonism (Montaigne’s diffident ‘
que sçais-je?
’), philosophers intrepidly armed themselves with reason.
    First outlined in
The Advancement of Learning
(1605), the empiricism of Francis Bacon – that aristocrat among English intellectuals – boldly claimed (
contra
the sceptics) that sufficiently reliable knowledge could be achieved by disciplined recourse to experience: man had the capacity, right and duty to know the world, the human epitome included, through the five senses. To parry any clerical jealousy over what might be taken as prying into God’s secrets – forbidden knowledge – the philosophical Lord Chancellor made a discreet and dutiful concession: investigation ‘must be bounded by religion, or else it will be subject to deceit and delusion’. But man was charged to read the Book of God’s Works no less than the Book of His Words: Nature as well as Scripture was a God-given fount of truth.
    Abstract reason was unsatisfactory because arrogant, and so science had to be grounded in modest experience – modelled not on the solipsistic spider spinning her web from within herself but on the busy bee gathering nectar from the flowers. Empirical knowledge, too, had its weaknesses, and Bacon warned of the distortions, both individual and collective, inherent in the senses, highlighting the four ‘idols’ (or illusions) which warped perception: those of the cave, herd, theatre and market-place. (The philosophical anti-idolatry that so animated Bacon clearly mirrored its Protestant iconoclastic twin.) This did not mean that the testimony of the senses was to be rejected; rather, it had to be kept on the straight-and-narrow by methodical fact-gathering, recourse to the supports of instrumentation, crucial experiments and submission to collective judgement.
    Bacon’s programme for the advancement of learning thus sidestepped the uniquely divine soul and occupied itself with the role of the ‘sensitive’ soul, the operation of the senses. Indeed, that wily statesman ceded the soul to the divines: ‘true knowledge of the nature and state of the soul’, he shrewdly allowed, ‘must come by the same inspiration that gave the substance.’
    *
    More concerned than the utilitarian Bacon with theorizing as an end in itself was René Descartes. Educated by Jesuits who introduced him to natural philosophy, including the Galilean astronomy, he initially enlisted as a gentleman-soldier before settling to the scholarly life, taking up mathematics and the physical sciences. By his mid-twenties his brilliant mind had glimpsed the possibility of combining algebra and geometry into analytical geometry; and on 10 November 1619, in a quasi-mystical experience recounted in his
Discours de la méthode
(Discourse on Method: 1637), he solemnly dedicated himself to the pursuit of truth, determining to doubt all conventional beliefs root and branch, and to build philosophy afresh on the basis of indubitable first principles. Beginning with the one thing so self-evidently true it could not possibly be questioned, his own consciousness –
cogito