There are many references in the tax legislation to the taxpayer's intentions in their transactions. For example, the acquisition or sale of an asset may be treated differently for tax purposes depending on the person's purpose in holding it. If the amount of tax is made dependent on the personal circumstances of the taxpayer in this way, the law is said to contain subjective elements. The purpose of my study is firstly to take stock of the extent to which such subjective criteria exist in the Income Tax Act. Secondly, I will examine whether the subjective criteria are constructed and applied in the same way regardless of where in the law they are found. If there are differences, I will examine whether the differences are objectively justified, i.e. to what extent there are acceptable reasons for them. This assessment is made in the light of the fundamental requirements of tax legislation, such as comprehensibility, equal treatment and efficiency.