\documentclass[10 pt,a4paper,twoside,reqno]{amsart}
\usepackage{amsfonts,amssymb,amscd,amsmath,enumerate,verbatim,calc,graphicx}
\renewcommand{\baselinestretch}{1.2}
\usepackage{bm}
\usepackage{ragged2e}
\textwidth = 12.5 cm
\textheight = 20 cm
\topmargin = 0.5 cm
\oddsidemargin = 1 cm
\usepackage[abs]{overpic}
\evensidemargin = 1 cm
\pagestyle{plain}
\newcommand\blfootnote[1]{%
\begingroup
\renewcommand\thefootnote{}\footnote{#1}%
\addtocounter{footnote}{-1}%
\endgroup
}
\newtheorem{theorem}{Theorem}
\newtheorem{definition}{Definition}
\begin{document}
\justify
\centering
\title{\textbf{ON THE REFLECTION PROPERTY OF A CIRCULAR PARABOLOID}}
\maketitle
\author{\textbf{S. Aryan}}
\begin{abstract}
Text for abstract.
\end{abstract}
\section{Introduction}
\justify
This is the introduction.
\end{document}
When I run this code. I get the text "This is the introduction" printed without the initial space before the word "This." I want the paragraph to be justified but when I use \justify I lose the space before the first word that marks the beginning of a paragraph. Is there a way to resolve this trade-off? In order to make my problem more clearer, I have posted below an image that shows the paragraphs in my actual document.
I want the word "The" in the image to be shifted to the right to mark the beginning of a paragraph.


amsartusers require, that the first paragraph after section, subsection ... titles are not indented. – Zarko Jan 10 '17 at 18:47amsartas document class, that this is desired/requested behavior. All others paragraphs after first after section/subsection .. tiles are indented. – Zarko Jan 10 '17 at 18:56amsartmake all paragraphs indented, but this rule you override with commands\centeringand\justify. – Zarko Jan 10 '17 at 19:24\titleand\authorit means the document won't meet the journal style guidelines and complicates extracting the metadata to put into the various databases of author/title information – David Carlisle Jan 10 '17 at 20:50