or, by extraordinary restraints, to force from 
a particular species of industry some share of 
the capital which would otherwise be employed 
in it, is, in reality subversive of the great 
purpose which it means to promote. It retards
instead of accelerating, the progress of 
the society towards real wealth and greatness
and diminishes, instead of increasing, the 
real value of the annual produce of its land 
and labour. 
All systems, either of preference or of restraint
therefore, being thus completely taken 
away, the obvious and simple system of natural 
liberty establishes itself of its own accord. 
Every man, as long as he does not 
violate the laws of justice, is left perfectly 
free to pursue his own interest his own way, 
and to bring both his industry and capital into 
competition with those of any other man
or order of men. The sovereign is completely 
discharged from a duty, in the attempting 
to perform which he must always be exposed 
to innumerable delusions, and for the proper 
performance of which, no human wisdom or 
knowledge could ever be sufficient; the duty 
of superintending the industry of private people
and of directing it towards the employments 
most suitable to the interest of the society
According to the system of natural 
liberty, the sovereign has only three duties to 
attend to; three duties of great importance
indeed, but plain and intelligible to common 
understandings: first, the duty of protecting 
the society from violence and invasion 
of other independent societies; secondly, the 
duty of protecting, as far as possible, every 
member of the society from the injustice or 
oppression of every other member of it, or 
the duty of establishing an exact administration 
of justice; and, thirdly, the duty of erecting 
and maintaining certain public works
and certain public institutions, which it can 
never be for the interest of any individual
or small number of individuals to erect and 
maintain; because the profit could never repay 
the expense to any individual, or small 
number of individuals, though it may frequently 
do much more than repay it to a 
great society
The proper performance of those several 
duties of the sovereign necessarily supposes
certain expense; and this expense again necessarily 
requires a certain revenue to support 
it. In the following book, therefore, I shall 
endeavour to explain, first, what are the necessary 
expenses of the sovereign or commonwealth; 
and which of those expenses ought 
to be defrayed by the general contribution of 
the whole society; and which of them, by that 
of some particular part only, or of some particular 
members of the society; secondly, 
what are the different methods in which the 
whole society may be made to contribute towards 
defraying the expenses incumbent on 
the whole society; and what are the principal 
advantages and inconveniences of each of 
those methods; and thirdly, what are the reasons 
and causes which have induced almost all 
modern governments to mortgage some part 
of this revenue, or to contract debts; and 
what have been the effects of those debts upon 
the real wealth, the annual produce of the 
land and labour of the society. The following 
book, therefore, will naturally be divided 
into three chapters