Abstract
<jats:p>The article provides a comprehensive theoretical study of the genesis of scientific approaches to the interpretation of the investment process within the leading economic schools from the 17th century to the present. It is determined that the investment process is a dynamic, multi-stage, and polystructural category that reflects the transformation of temporarily free financial resources into real, financial, or intellectual capital. The authors thoroughly analyze the evolution of perceptions of investing, starting from mercantilism, where investment actions were viewed through the lens of accumulating national wealth through the stimulation of foreign trade and State regulation. The contribution of the physiocrats is highlighted, who argued for the exclusive productivity of capital investments in the agricultural sector and laid the foundations of economic liberalism. Special attention is paid to the doctrine of the classical school (A. Smith, D. Ricardo, J.-B. Say, J. S. Mill), whose representatives defined capital accumulation as the fundamental driving force of economic growth and introduced the postulate of the identity of savings and investment. The Marxist concept is examined, in which investment is interpreted as an objective stage of capital circulation, and the role of capital and the cyclicality of fixed asset renewal are also analyzed. Within the neoclassical approach (A. Marshall, L. Walras, I. Fisher), attention is focused on the microeconomic motivation of rational agents, where the investment decision is considered as a result of intertemporal choice adjusted by the real interest rate. The Keynesian approach is analyzed in understanding investment as an internally unstable driver of the economy, which depends on the psychological expectations of business and requires government stimulation of aggregate demand through the multiplier mechanism. The present scientific work reveals the positions of monetarism regarding the priority of a stable monetary and credit environment and the theory of rational expectations, which emphasizes the importance of full information for agents and the predictability of government policy for investment activity. Separately, the approaches of the new institutional economics concerning the impact of «collective institutions», property rights, and transaction costs on the investment environment are highlighted. The analysis concludes with an overview of behavioral economics, which abandons the conception of full rationality and explores investment processes through the lens of cognitive biases, emotional influence, and the limited rationality of agents. It is determined that the modern understanding of the investment process is integral and encompasses material, institutional, and behavioral aspects.</jats:p>