In a remarkable letter to Windham[140] of 1806, Mackintosh gives his estimate of Burke, and takes some credit to himself for having discovered, even in the time of his youthful errors, the consistency of Burke's principles, as founded upon an abhorrence of 'abstract politics.'[141] Politics, he now thought, must be made scientific by recognising with Burke the supreme importance of prescription and historic continuity, and by admitting that the philosophers had not yet constructed a science bearing to practical politics the same relation as geometry to mechanics. He applied his theory to the question of parliamentary reform in the _Edinburgh Review_.[142] Here he accepts the doctrine, criticised by James Mill, that a proper representative system must be judged, not, as Mill maintained, solely by the identity of its interest with that of the community at large, but by its fitness to give power to different classes. It follows that the landowners, the professional classes, and the populace should all be represented. And he discovers that the variety of the English system was calculated to secure this end. Though it was only in a few constituencies that the poorest class had a voice, their vote in such places represented the same class elsewhere. It was as well that there should be some extreme Radicals to speak for the poorest. But he thinks that any uniform suffrage would be bad, and that universal suffrage would be the most mischievous of all systems.[143] That would mean the swamping of one class by all--a tyranny more oppressive, perhaps, than any other tyranny. If one class alone were to be represented, it should be the favourite middle class, which has the 'largest share of sense and virtue,' and is most connected in interest with other classes.[144] A legitimate aim of the legislator is, therefore, to prevent an excess of democracy. With Mackintosh it seems essential not simply to suppress 'sinister interests,' but to save both the aristocracy and the middle class from being crushed by the lower classes. The opposition is vital; and it is plain that the argument for the aristocracy, that is, for a system developed from all manner of historical accidents and not evolved out of any simple logical principles, must be defended upon empirical grounds.