But thought cannot be appropriated. In thought there is no material product to be made the object of a proprietary right. There is no “thing” to be possessed or alienated. The law can only, therefore, give the exclusive use of an idea to one person by injuriously limiting the intellectual activity of all others. A Patent-right, therefore, is less a “property in ideas” than a monopoly of thought. Again, a true right of property is universal in its application; it extends to the products of all industry, however humble. But it is instinctively felt, that a proprietary right applied to every individual idea would be essentially absurd. Patent-Law, therefore, is essentially partial in its application. It picks out certain favourite ideas, and confers on them an anomalous and oppressive privilege. There seems no good reason why the ideas of inventors should be especially favoured. An invention is a means to a special end, and should be recompensed by him who has the end in view. If any ideas deserve a public recompense, it is those general ideas whose application is of universal utility. But Patent-Law ignores the discoverer of general ideas, and while conferring rewards, at the expense of the community, on empty schemers and puffing tradesmen, it passes over the services of a Newton or an Adam Smith. The law of Copyright, indeed, gives to the philosopher a right of property in his published and material works, but it leaves (most justly) his ideas to be used and elaborated by whoso can and will. Again, Patent-Law is founded on a conventional, not a natural, right. It is not, like the ordinary law of property, based on an universal intuition of the human conscience, but it is one of those laws by which unwise legislators have striven so long and so vainly to give an artificial stimulus to human industry. Hence the arbitrary nature of its enactments. The ordinary right of property is unlimited in its duration—passing from generation to generation. But common sense revolts, instinctively, against a perpetual monopoly of thought. A Patent-Law, therefore, can never be more than a weak compromise with principle—the legislator undertaking to secure to the patentee his ideal property during the biblical term of seven or fourteen years. Now, if the inventor have a right at all, he has a right to more than this. To cut down a real and acknowledged right of property to seven, or even fourteen, years were a grievous wrong. Patent-right goes too far, or not far enough. Either a Patent is no right at all, or it is a right for all time. If ill-founded, it is a robbery of the public; if well-founded, of the patentee.