'For,' he exclaimed, 'either this question of fossils belongs to a vulgar, mechanical science, alien to metaphysic, and hence not to be discussed in an assembly met to contend solely about philosophical questions, or it verily pertains to the true, the sublime science of dialectic; in which case it must be discussed according to the laws of dialectic, which alone allows theory to ascend to the sphere of pure speculation.'

'I understand you, Messere,' said Leonardo patiently; 'I have thought of what you say. But the alternative is not as you state it.'

'Not as I state it?' cried the veteran smiling angrily, 'not as I state it? Then, sir, pray let us hear how you propose to state it!'

'Nay, nay; I had no wish to offend. In fine, I spoke but of shells. I think—nay, Messere, but there is no vulgar science, nor is there sublime science. There is but one science; that which is based upon the experience of the senses.'

'The experience of the senses? Then where would you put the metaphysic of Aristotle, of Plato, of Plotinus, and of all the ancient philosophers who speculated upon God, upon the soul, and upon the essences? Would you say of all this——?'

'That it is not science,' replied Leonardo calmly. 'I recognise the greatness of the ancients, but not in that respect. In science they mistook the road. They wished to learn what was beyond the reach of knowledge, and what was within their reach they despised. They led men astray for many ages. Discussing matters which admit not of proof, it is impossible for men to agree; the less so if they would make up for the lack of proof by vehemence of clamour. He who truly knows has no occasion to shout. The voice of truth is unique; and when it has spoken, all the noise of dispute must be hushed. If the cries continue, it means that the truth has not yet been found. Do we need mathematical dispute as to whether twice three be six or five? or whether the angles of a triangle be or be not equal to two right angles? In these instances doth not contradiction cease in the presence of truth? and is not truth to be enjoyed as it never can be enjoyed in sophistical and imaginary sciences?'

Leonardo would have spoken further, but after a glance at the face of his opponent he became silent.

'Ah!' said the doctor of scholastic, ironically, 'I thought we should arrive at an agreement! You and I were certain to understand one another! But one thing I do not understand. Pardon the ignorance of an old man! If our knowledge of God and of a future life, not being confirmed by the testimony of our senses, but by the testimony of Holy Writ——'

'I spoke not of this,' interrupted Leonardo; 'I leave out of the dispute the books inspired by God, for they are of the substance of supreme truth.'

He was not allowed to continue; uproar ensued. Some shouted, some laughed; some, springing from their chairs, turned wrathful faces on him, while others, shrugging their shoulders, left the assembly.