There are no inborn truths for Locke.
All knowledge is empirical, received through the senses.
The mind has no private truths. It is originally a tabula rasa , a blank tablet, on which external things make their impression through the senses. Even our inward ideas are products of outward sensations. The mind cannot have its own ideas independent of sense-perception. We know nothing that is not perceived through the senses or reflected by the mind on the basis of sense-perception.