On the other hand, it may be that militarism so largely prevails, that all available men are wanted in warfare. If, then, the military organization is not so highly developed, that slaves can be employed in warfare without any danger, slavery is not likely to exist, though it might be economically of great use.
There are other causes, which we may call external. However much slaves are wanted, there must be a coercive power strong enough to make the keeping of slaves possible. The following causes tend to increase this coercive power:
1º. Living in fixed habitations. Besides the effect this has on the growth of industry, it makes the escape of slaves more difficult and the surveying of slave labour easier.
2º. Living together in large groups. In a small group any [[260]]increase in the number of slaves would soon become dangerous to the maintenance of power by the freemen within the group, and an escaping slave would soon be out of reach of the group.
3º. The preserving of food. Besides having some economic effects of which we have treated above, it makes living in large groups and in fixed habitations possible; moreover it attaches the slave to his master’s home; for he knows he will get there sufficient food in the time of scarcity, whereas, if he escaped, he would have to shift for himself.
4º. The existence of a somewhat homogeneous group of tribes maintaining constant relations with each other greatly accelerates the growth of slavery, especially by means of the slave trade. Twenty tribes, living separately, have, each for itself, to invent slavery; but when twenty tribes maintain relations with each other, as soon as one of them has invented slavery, the other 19 have it ready-made before them.
Recapitulation.
| Furthering the growth of slavery. | Hindering the growth of slavery. | |
| I. Internal causes. | ||
| A. General: | 1º. Subsistence easily acquired and not dependent on capital. | 1º. Subsistence dependent on capital. |
| 2º. Subsistence not dependent on capital, but difficult to acquire. | ||
| B. Secondary, economic: | 1º. Preserving of food. | 1º. Female labour making slave labour superfluous. |
| 2º. Trade and industry. | ||
| 3º. A high position of women. | ||
| C. Secondary, non-economic: | 1º. Slaves wanted for military purposes. | 1º. Militarism making slavery impossible.[[261]] |
| II. External causes: | 1º. Fixed habitations. | |
| 2º. Living in large groups. | ||
| 3º. Preserving of food[328]. | ||
| 4º. The existence of a homogeneous group of tribes. | ||
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